Adam Daily's Portfolio

Grouping Minor League Hitters by Power & Contact

I am going to make a confession. I love combing through minor league data. It is fun to search the minor league leaderboards and try to find those few players that come out of nowhere to become big league regulars. Do not get me wrong, I enjoy watching the top prospects in the game like Bobby Witt Jr. and Julio Rodriguez, but there is a certain satisfaction you get from finding that unheralded prospect that has success at the major league level. It is akin to finding and supporting that local band before they made it big. It validates your opinions and shows that you have some decent taste.

But how do you go about finding these diamonds in the rough? To find a good local band, you can just go to a lot of local concerts. To find a future major leaguer (using data alone), there are a multitude of factors to consider. What level have they had success at? How old are they? What position do they play? Are they in a hitter-friendly league? The options are endless, and that is just the first problem. The other problem is that there are so many minor league players to sift through. (Apparently MLB agrees given that they continue to try and reduce the number of professional teams). That is why I decided to use clustering analysis to quickly group minor league players to see which players are the most likely to succeed at the Major League level.

Data Collection

There may be a lot of minor league data, but minor league fielding data is still sparse. I would prefer to incorporate minor league defense into this project, but given the data restrictions, I decided to focus solely on a player’s offensive value.

For my data set, I gathered all affiliated minor league hitting data from 2006 to 2019 and then grouped each hitter’s minor league career totals across three levels of competition: Upper Minors (AAA & AA), A-Ball (A+ & A), and Complex-Ball (any level that is not full-season). I then removed any player that did not accumulate three hundred or more plate appearances in their grouped level. I split the data into three separate groups, because the competition levels are drastically different. It would be imprudent to treat AAA statistics the same as rookie-ball statistics. I considered splitting by each individual level of competition, but this would create too many subsets and there would be very few players that would generate three hundred or more plate appearances at every minor league level.

There are many factors that go into being a successful hitter, but the two factors I chose to spotlight are a player’s power and his ability to make contact. I know plate discipline is important, but I prefer to use only two variables for cluster analysis visualizations to avoid complicated visualizations. Besides, if you hit the ball hard enough and frequently enough, no one is going to mind if you are a free swinger. Just ask Vladimir Guerrero.

I used a player’s ISO to represent his power and his strikeout rate to represent his ability to make contact. Ideally, I wanted to use Statcast data to evaluate power and miss rate to evaluate a player’s contact ability. However, without access to minor league Statcast data, I had to settle for this method.

K-Means Clustering

I decided to utilize a machine learning technique, called k-means clustering, to group the players by their ISO and strikeout rate. This helped me determine which minor league players have the best chance of succeeding in the majors. There are three distinct groups of hitters across my three levels of competition. Below are the clusters for the players in the upper minors.

Upper Minors

I find this cluster group interesting because the groups are players that have below average power and make an above average level of contact (Cluster 1). Players that have below average power and make below average contact (Cluster 3). And players that have above average power (Cluster 2).

With the players grouped into clusters, I decided to see how each cluster of minor leaguers performed at the Major League level. The first thing I looked for was players from each cluster that recorded three hundred or more plate appearances in a single season. This indicates that the player was receiving a reasonable amount of playing time and was a valued member of his team for at least one season.

Next, I looked at the maximum wRC+ that each minor league player recorded in a season at the Major League level with a minimum of three hundred plate appearances. I chose maximum wRC+ instead of career wRC+ because I wanted to focus solely on a player’s peak value and not include his decline phase. This means that several players will be over-valued for a half-season of performance, but it also does not penalize players that were legitimate MVP candidates for several seasons that had a precipitous decline.

The first thing that caught my attention was that only 20.8% of players went on to have at least one MLB season with three hundred or more plate appearances regardless of what cluster they were in. The next thing is that the players in Cluster 2 were far more likely to perform in the majors. The data would suggest that a higher ISO in the upper minors is more likely to contribute at the MLB level.

A-Ball

Once again, the clusters followed a similar pattern with Cluster 1 being composed of players with well above average power. Cluster 2 consisting of players that make above average contact with below average power and Cluster 3 made up of players with below average contact ability, but this time the cluster allows for a wider spread of ISO than the clusters in the Upper Minors.

There were fewer players that played in MLB across the board. This is unsurprising considering that many of these players did not make it to the upper levels of the minors. The cluster with above average power out-performed the other two clusters yet again.

Complex-Ball

For the third time, the clusters followed a similar pattern. Cluster 3 being players with above average power, Cluster 2 being comprised of players with below average contact ability and roughly average power, and Cluster 1 being players with below average power, but above average contact ability. This makes it a bit easier to compare players across the various levels of competition.

These percentages for success are dangerously low for each cluster, but this is partially due to selection bias. There are few top prospects that spend multiple seasons outside of full-season ball, so the most talented players do not accumulate the three hundred plate appearances required to be in my data set. Even with this wrinkle, the pattern remained the same with the players with above average power having the most success in the majors. The odds of becoming an impactful major league hitter are small no matter which cluster the hitter belongs. However, the minor league players with the greatest chance of success are the players who post ISO rates well above league average.

2022 Top Prospects

With the historical minor leaguers assigned to their clusters, I turned to this season’s top prospects to see which clusters they belong to for each level of competition. Below is a table showing each position player prospect with a 50 or higher FV rating from FanGraphs.com with their cluster number for each level of competition. I highlighted the cluster with the highest success rate green, the cluster with the second highest success rate yellow, and the cluster with the lowest success rate as red across all levels. Any level that the player did not accumulate three hundred plate appearances I left blank, and I removed the players that did not accumulate three hundred plate appearances at any level.

*Please keep in mind that cluster analysis is meant for grouping a set of objects and is not a projection system. So, just because a player is in a certain group that does not mean he is going to do well or fail at the major league level. A projection system requires many more variables and rigorous analysis to forecast properly. Cluster analysis is a quick way to view trends and summaries, but it should not supersede a projection system.

Looking for a Breakout Performance

Every franchise is looking for that player who seems to come out of nowhere to be a major contributor in their lineup. Players like Jose Bautista who went from 1.8 WAR in 2009 to 6.5 WAR in 2010 or Justin Turner who went from 0.5 WAR in 2013 to 3.4 WAR in 2014. The cost for acquiring these players was affordable because they were no longer prospects and most of the league had written them off as potential everyday players.

If a team had the ability to identify which players are most likely to exceed industry expectations, they would have a significant advantage over their competition. That is why I decided to create a model to identify potential breakout performers.

Methodology

The first thing I needed to do was to define what constitutes a breakout performance. I thought of several different definitions, but I decided to define a breakout performance as any player that exceeded their career high WAR in a single season by at least 2.0 WAR. So, if a player had recorded a season of 0.0 WAR, they would need to have at least a 2.0 WAR season. If a player had recorded a season of 1.0 WAR, they would need to have at least a 3.0 WAR season and so on and so forth.

I chose 2.0 WAR, because it seemed like a reasonable balance of making it a difficult threshold for a player to reach, but also not limiting the number of positive cases. If there are not enough positive cases in a model, it can hurt the model’s performance. I also thought that 2.0 WAR is what the average MLB player produces in a full season, so using that as a cutoff would be akin to a team gaining a league average player for no cost.

Using a binary variable instead of a continuous variable to define a breakout performance means that I can use a logistic regression model to predict which players are the most likely to outperform their previous seasons. Now that I have determined which model to use, the next step is to determine what the data set will be.

Collecting the Data

To create a data set, I started with players that started their domestic professional baseball career in 2006 or later. I chose 2006 as a cutoff, because it is the furthest back that Minor League data is available on FanGraphs, and I only wanted to include players with their full minor league history.

I also decided to only include 2006 to 2019 MLB data. The shortened 2020 season would be difficult to include in a project of this nature, so I decided to only include full seasons in the data set, and this would still allow me to use 2021 data to check the validity of the model.

Next, I limited the data set to include only players with three hundred or more career Major League plate appearances. I chose three hundred, because it is a reasonable number of plate appearances for evaluators to form an opinion on a player, while still allowing for further growth and development at the Major League level.

Allowing players with fewer than three hundred plate appearances would allow for more prospects in the analysis. However, the objective of this project is to find players that are most likely to outperform their previously observed production. Prospects do not have enough of a Major League record to compare to, so it would be unwise to include them in the model.

Building the Model

After these restrictions, the data set consisted of 1684 players. The next thing I needed to do was determine which variables to use in the model. I considered a variety of Major League and Minor League statistics, the prospect’s highest Baseball America prospect ranking and personal details like height, weight, age, position, and birth country. After several model implementations, the final model consisted of eight variables: season age, BMI, previous season WAR, season high WAR, MLB ISO, MLB speed score, MiLB walk rate, and MiLB batting average. Below are the coefficients for each variable in the model.

Most of the variables have a positive value except for season high WAR and age. This means that the older a player is and the higher their season high WAR is, the lower their chances are of having a breakout performance. This may seem counterintuitive for season high WAR. However, it makes sense that a player like Bryce Harper or Mike Trout would have more difficulty producing a 12-win season than someone like Justin Turner needing to only produce a 2.5-win season in 2014. The higher your breakout threshold is, the more things like injuries can derail your chances of posting an extremely high WAR total.

The other thing that caught my attention is that BMI has a positive coefficient value instead of a negative one. Sometimes, a high BMI can be an indicator of poor health, but BMI is an extremely crude measurement. It does not consider things like muscle mass or waist size and many professional athletes are obese by this BMI measurement when they just have far more muscle mass than the general population. My theory is that many players in the model with a high BMI are extremely fit individuals with high muscle mass and this is what is causing a positive coefficient value. If I had access to more precise body measurements, I would certainly include it in the modeling process.

Testing the Model

With the model completed and the 2021 season officially in the books, I can now examine the accuracy of the model for this past season. There were 303 position players with over three hundred career plate appearances in the data set and below is a confusion matrix showing how many of the model’s predictions were correct.

The model’s overall accuracy was 83.83% with 254 of the 303 total predictions being correct. With 244 of the 250 predicted non-breakouts being correct and ten of the fifty-three predicted breakouts being correct. These results are consistent with the testing set I used to calibrate the model, so I am satisfied that the model is performing as expected.

The model is clearly better at distinguishing which players are not going to breakout versus finding players that will breakout. Since many breakout performances seem to come out of nowhere, it makes sense that breakouts would be more difficult to identify. This means that the model is better at eliminating a large amount of breakout candidates and finding potential breakout candidates, rather than accurately predicting breakout candidates.

For anyone who is curious, below is a list of the sixteen players that had a breakout season in 2021 with their 2021 WAR, their previous season high WAR and their predicted chance of a breakout performance.

There are some hits in here with Vladimir Guerrero Jr., Austin Riley, Kyle Tucker, and others easily reaching the 2-win improvement threshold, but there are also some misses like Shohei Ohtani, Bryan Reynolds and Trea Turner.

I think Ohtani is the most egregious miss, but I would like to point out that he had no minor league data and a poor 2020 showing that severely brought down his breakout prediction. So, the result looks bad, but I understand why the model missed on his 2021 breakout.

2022 Breakout Candidates

Since the model seems to be serviceable. The next step is to look for potential breakout performances in 2022. Below is a list of the sixty-one players that the model predicts will breakout along with the player’s most recent team, their 2022 season age, 2021 WAR, the WAR threshold for a breakout season, and the percent chance the model predicts for the player having a breakout season.

Before anyone starts buying Garrett Hampson and Sam Hilliard stock, please remember that the model is far more accurate at predicting which players will not breakout, so there are many players on this list that will not reach their breakout threshold. However, the chances of finding a breakout season from a player not on this list is going to be much lower.

It is my hope that this model will continue to identify future MLB contributors and I look forward to revisiting the subject when more data from Statcast is available. I believe that player measurements like exit velocity and launch angle could drastically improve model performance and I plan to incorporate them into the model in the future.

Click here for GitHub code.

What Pitch Should You Throw Next?

There are few things I enjoy in baseball more than the pitcher vs. hitter dynamic. Everyone likes to see highlight plays like a great catch or a mammoth home run, but those plays are few and far between. I believe that the tension created in a drawn-out plate appearance is where baseball is most enjoyable. Every pitch is meaningful, and the strategy of the game is on full display. The pitcher is trying to decide the best way to get the hitter to produce an out and the hitter is doing everything he can to thwart the pitcher.

This dynamic of the baseball has always fascinated me. I was curious how pitchers and catchers decided which pitch was correct to throw in a situation. There are plenty of tools available to them that were not readily available when I was a child. Like heat maps made from pitch-tracking data, but these tools show results without the context of what previous pitches were thrown in the plate appearance. Heat maps provide useful data, but the real art of pitching is being able to set up a hitter to take advantage of a hitter’s weaknesses. If a pitcher throws the same pitch in the same location every time, eventually the hitter is going to catch on and change his strategy accordingly. So which sequence of pitches is the most effective at retiring hitters? This is the question I attempted to answer with this article.

Methodology

To get my initial data, I imported every regular season pitch from Baseball Savant from 2008 to 2020. This gave me almost 9 million rows of data. The next step was to aggregate the different pitch types. Baseball Savant has fourteen distinct pitch types, but I decided to group them into four categories of pitches: fastballs, curveballs, sliders, and changeups. The groupings are in the table below.

My Grouping	Baseball Savant Pitches
Fastballs	4-Seam Fastballs, 2-Seam Fastballs, Sinkers
Curveballs	Curveballs, Knuckle Curves, Slow Curves, Eephuses
Sliders	Sliders, Cut Fastballs
Changeups	Changeups, Split-fingers, Forkballs, Screwballs

The one pitch missing from the table is the knuckleball. Knuckleball pitchers are exceedingly rare, and they do not rely on pitch sequencing, so they were excluded from my analysis.

The main reason I grouped these pitches together was to avoid small sample issues when looking at pitch sequences in a plate appearance. Small sample size may not seem like an issue for almost 9 million rows of data, but the number of permutations in a plate appearance grows rapidly. There may be a few quibbles with how I grouped the pitches together, but I believe it is an accurate representation of the major types of pitches in baseball.

After I created my pitch types, the next step was to create zones for where the pitch crosses the plate. I decided to split the locations into nine separate zones. The nine zones are:

Low and Outside
Low and Inside
Low and Middle
Middle and Outside
Middle and Inside
Middle and Middle
High and Outside
High and Inside
High and Middle

The first part of the zone name corresponds to the pitch height. The second part corresponds to the plate location.

For me to use inside and outside zones, I needed to consider the handedness of the hitter. If a hitter is right-handed, anything greater than or equal to 0.28 feet in the plate_x column was considered outside. Anything less than or equal to -0.28 feet in the plate_x column was considered inside. For left-handed hitters anything greater than or equal to 0.28 feet in the plate_x column was considered inside. Anything less than or equal to -0.28 feet in the plate_x column was considered outside. Everything else was considered the middle of the plate.

To determine the zones for the height of pitches, I first calculated the strike zone length by subtracting the bottom of the strike zone height from the top of the strike zone height. I then took this length and divided by three. Any pitch above the lower boundary of the top third was considered a high pitch, and any pitch below the upper boundary of the bottom third was considered a low pitch. The remaining section was considered middle height.

Next, I grouped all the pitch sequences by plate appearance. I then removed any plate appearance that had missing pitch data. This left me with over 2 million plate appearances to analyze. I decided to look at plate appearance results so that I could evaluate the entire battle at the plate instead of each individual pitch. This did limit the amount of data to analyze, but I believe it gives a more accurate look at what pitch sequences truly work when a pitcher is trying to retire a hitter.

The last thing I wanted to account for were platoon splits in a plate appearance. Being a righthanded pitcher and throwing a breaking ball low and outside to a righthanded hitter is different from throwing a breaking ball low and outside to a lefthanded hitter. It would have been misguided to not separate those occurrences, so I decided to create two separate groups. The first group is pitchers with a platoon advantage and the second group is pitchers with a platoon disadvantage.

Results

Now that I have explained the data gathering process, it is time to explain the results. As I mentioned in the previous section, I will be looking at situations where the pitcher had the platoon advantage and where he had the platoon disadvantage. I will also be summarizing the plate appearance results in two ways. The first will be by utilizing pitch type alone. The second will be by utilizing both the pitch type and location. I did this, because the sample sizes for the results using pitch type and location get small quickly and the results using pitch type alone are far more useful for analysis in those instances. With all that said, it is time to look at the results for the first pitch in a plate appearance.

First Pitch of Plate Appearance

From this table, we can see that starting a plate appearance with a changeup is generally a bad idea with or without the platoon advantage. I was surprised by how close the wOBA values were for fastballs, curveballs, and sliders when a pitcher had the platoon disadvantage. I thought that there might be more separation like the splits seen between pitches when the pitcher has the platoon advantage. I am not sure why there was such a large split between fastballs/sliders and curveballs/changeups when the pitcher had the platoon advantage. However, I suspect that there could be some selection bias due to relievers entering the game with favorable matchups.

Next, I reviewed the summary by pitch type and location. This is the only pitch type and location table I will show in its entirety. Going forward, I condensed the table to only show the best and worst pitch sequences by wOBA.

There are plenty of conclusions that can be drawn from the table above, but one thing I found interesting was how the same pitch type could be thrown in a different location and have drastically different results. From the previous table, we saw that curveballs are generally not the best pitch to be thrown to start a plate appearance if you have the platoon advantage. However, if you throw the curveball high and outside or middle and outside, your chances of succeeding increase substantially. I believe this disparity shows just how important pitch execution is for a pitcher. A pitcher could have the perfect pitch selection to retire a hitter, but if you miss your intended location by six inches or more it does not matter.

First Two Pitches of Plate Appearance

Once again if a pitcher has the platoon advantage, it seems like it is not a good idea to throw a changeup for the second pitch of a plate appearance. The only time throwing a changeup is not the worst option is when you threw a changeup in the first pitch of the plate appearance. Starting a plate appearance with a fastball gives the most options for a successful second pitch with fastballs, curveballs and sliders all yielding decent results. If you started the plate appearance with a slider, it would be sensible to continue throwing breaking balls to achieve the best results.

If you are a pitcher without the platoon advantage, breaking balls seem to be your best bet for a successful outcome. Throwing a curveball or slider for the second pitch of a plate appearance is far superior to throwing a fastball or changeup regardless of what you threw for the first pitch.

Going forward, I will only show the top five and bottom five pitch sequences by pitch type and location with a minimum of 300 plate appearances. I do have the results for each pitch sequence, but it would be far too large of a visual for the purposes of this article.

Top 5 Sequences-First Two Pitches (Min 300 PA)

Bottom 5 Sequences-First Two Pitches (Min 300 PA)

First Three Pitches of Plate Appearance

After looking at these tables, it appears that throwing a fastball for the third pitch in the plate appearance is a poor option regardless of what the first two pitches were. I assume that this happens due to the count in the plate appearance. Usually, pitchers that fall behind early in the count need to challenge a hitter with a fastball in the strike zone. This gives the hitter a significant advantage and most likely skews the results a bit. In the future, I may revisit the issue and adjust for count, but I fear that doing so will restrict my sample size even more.

Top 5 Sequences-First Three Pitches (Min 300 PA)

Bottom 5 Sequences-First Three Pitches (Min 300 PA)

First Four Pitches of Plate Appearance

This section is a bit different from the previous ones. There are now 256 unique pitch type combinations, and it was too difficult to make the full table presentable. Therefore, I split the table into four smaller tables based on the first pitch in the plate appearance. I also decided to abandon the top five and bottom five pitch and location sequences, because there were over 250,000 combinations for each platoon situation and only about twenty total combinations that had over 300 plate appearances with results.

First Pitch Fastball

First Pitch Curveball

First Pitch Slider

First Pitch Changeup

Once again, it appears that throwing a fastball for the fourth pitch in the plate appearance is a poor option regardless of what the first three pitches were. The near universal increase in walk rate for sequences with a fastball as the fourth pitch provide more evidence that the increase in wOBA is heavily count related. Breaking balls continued to be the most effective pitch thrown in most situations. It makes sense that pitchers have started to eschew their fastball for secondary pitches in recent years.

Conclusions

I could continue to parse the data further for longer plate appearances, but I do not want to belabor the point. There is far more analysis that can be done with these results, but I believe that this is a satisfactory introduction for a broad topic. I am confident that the same process could be modified to suit an individual player strategy, but that is beyond the scope of this article. With that said, here is a summary of my findings:

If a pitcher has the platoon advantage, a fastball or slider is the most effective pitch to throw to start the plate appearance.
Pitch location is at least as important (if not more so) than pitch selection.
In most situations, throwing a breaking ball is going to be the most effective pitch.
In most situations, throwing a changeup is going to be the least effective pitch.
The more fastballs a pitcher throws later in the plate appearance, the less likely they will have a favorable outcome.

Click here for GitHub code

Your Team’s Prospects Are Probably Not Going to Work Out

Serious prospect hounds know that only about 10% of minor leaguers ever participate in a Major League game in their career. However, even the most discerning fans can be deluded into believing that their team’s farm system can overcome the odds and build a perennial contender based on their farm system alone.

I decided to investigate how much average WAR a prospect generates based on their ranking in Baseball America’s Prosect Handbook. I used a similar process in a previous article where I calculated the amount of WAR based on the next six seasons of a player’s career since being listed instead of when a player makes their Major League debut. This means that players closer to the Majors get a boost to their value, since they will have more opportunities to accumulate WAR than players in the lower minors.

Next, I grouped the players by their ordinal ranking in their organization from the 2001 to 2015 seasons and calculated each group’s average WAR to create the visualization below.

That is a steep decline, but it is not unexpected. Most prospects that ascend to the top of their team’s list have flourished in the lower minors or have a higher pedigree than their minor league compatriots. Many top prospects are also perceived as being closer to big league ready. It makes sense that these types of players would produce more value given my methodology. Players that are ranked lower can still be successful in the Major Leagues, but the profusion of prospects that fail to make it to the Majors keeps these group’s average much lower than the higher ranked players in an organization.

This is a decent start, but it does not account for differences in an organization’s minor league depth. The fifth ranked prospect for a rebuilding team with plenty of depth is likely more talented than a fifth ranked prospect in a competing team’s depleted farm system. To account for the quality differences between farm systems, I created a heat map of average WAR produced with the player’s ranking in the organization on the y-axis and the team’s farm system ranking on the x-axis.

As expected, higher values are in the top half of the heat map. The highest values appearing in the top left-hand corner. If Baseball America’s rankings are an accurate representation of minor league talent, the highest ranked players in the most talented farm systems should produce the most value.

Average WAR is a reasonable place to start. However, with so many prospects in my dataset failing to reach the big leagues, the distribution of player WAR value is heavily skewed to the right. When dealing with skewed datasets, it is more appropriate to use median values instead of average values. This is because outliers can heavily influence your results and the median calculation helps to mitigate the effects that outliers can have on your dataset. The next heat map was created the same way as the previous one, but with each group’s median WAR instead of average WAR.

Woof. This chart is much bluer than the previous one, but the pattern is similar with the top of the chart producing the most value. This graphic shows a more desolate view on prospect valuation, but front offices and fans do not necessarily care about summary statistics. They care about their individual player and how he will do in the future. It is nice to know the odds of success from the past, but it is not necessarily predictive of a player’s future. Players outperform baseball industry projections all the time. Who is to say that your team does not have a diamond in the rough? The next heat map attempts to provide a realistic showing of a best-case scenario for each prospect ranking. Each cell is the maximum amount of WAR produced in their respective cohort.

This graphic shows why GMs are reluctant to trade away their prospects. The general trend remains the same, but there are far more yellow and green boxes dispersed throughout the chart. Nobody wants to be known as someone who trades away a young star for three months of a role player. This heat map shows that Major League contributors can come from almost anywhere.

I am interested in players that the industry has overlooked. I believe it would be beneficial to identify these types of players to see if there is a possible blind spot in prospect valuation. The first thing I decided to do was limit the dataset to include only players that were ranked eleventh in their organization or lower. I could have drawn the line anywhere in the top 30, but the line chart from earlier seems to start to level off around this point and ten seems like a logical cutoff point.

The next step was to determine how much accumulated WAR is considered a success. I landed on 10 WAR being considered as a success. This cutoff is arbitrary, but I wanted to pick a lower cutoff value to accommodate for players that are in the lower levels of the minors and several years away from the Majors. These younger players may be as talented as older players but since I am not adjusting for a player’s team-controlled seasons, inexperienced players do not have the same opportunities to generate as much value as their teammates who are closer to the Majors. By keeping my threshold low, I should be able to mitigate some of the bias in my dataset.

There were 97 players who met my criteria and 127 occurrences of players ranked eleventh or lower that produced over 10 WAR in six seasons. With 25 players doing it twice, Denard Span doing it three times and Josh Donaldson doing it four times! Below is a summary table of each occurrence with an accompanying bar chart.

Year	Player	Position	Amateur Type	Team Rank	Rank in Organization	Highest Level Played	WAR
2001	A.J. Pierzynski	Position Player	HS	15	18	MLB	11.4
2001	Aaron Harang	Pitcher	4Yr	11	27	A+	12.2
2002	Aaron Harang	Pitcher	4Yr	19	16	AA	17.0
2011	Adam Eaton	Position Player	4Yr	22	30	Rk	14.6
2012	Adam Eaton	Position Player	4Yr	4	12	AA	15.1
2009	Alex Avila	Position Player	4Yr	28	20	A	10.8
2005	Andre Ethier	Position Player	4Yr	8	16	A+	11.2
2011	Andrelton Simmons	Position Player	JC	2	15	Rk	12.8
2007	Asdrubal Cabrera	Position Player	INTL	10	15	AAA	12.2
2007	Austin Jackson	Position Player	HS	7	18	A	11.7
2005	Ben Zobrist	Position Player	4Yr	22	16	A-	12.1
2006	Ben Zobrist	Position Player	4Yr	20	16	A+	18.5
2003	Bill Hall	Position Player	HS	16	18	MLB	10.7
2014	Blake Snell	Pitcher	HS	20	14	A	11.1
2001	Brandon Webb	Pitcher	4Yr	29	27	A	16.8
2002	Brandon Webb	Pitcher	4Yr	23	26	A+	22.4
2006	Brett Gardner	Position Player	4Yr	17	13	A-	14.7
2009	Brett Gardner	Position Player	4Yr	15	13	MLB	20.6
2011	Brian Dozier	Position Player	4Yr	13	30	A+	16.4
2001	Brian Lawrence	Pitcher	4Yr	8	11	AAA	11.3
2003	Brian McCann	Position Player	HS	2	28	Rk	14.9
2006	C.J. Wilson	Pitcher	4Yr	16	14	MLB	11.2
2007	Carlos Ruiz	Position Player	INTL	21	13	MLB	14.4
2012	Charlie Blackmon	Position Player	4Yr	16	11	MLB	16.9
2004	Chien-Ming Wang	Pitcher	INTL	27	12	AA	10.4
2003	Chone Figgins	Position Player	HS	5	28	MLB	15.8
2004	Chris Young	Pitcher	4Yr	30	19	AA	12.1
2014	Cody Bellinger	Position Player	HS	14	14	Rk	15.4
2015	Cody Bellinger	Position Player	HS	3	20	Rk	16.6
2013	Collin McHugh	Pitcher	4Yr	26	24	MLB	11.4
2013	Corey Dickerson	Position Player	JC	20	13	AA	10.5
2011	Corey Kluber	Pitcher	4Yr	7	26	AAA	21.4
2002	Covelli Crisp	Position Player	JC	30	18	A+	15.2
2003	Covelli Crisp	Position Player	JC	1	26	MLB	16.8
2003	Curtis Granderson	Position Player	4Yr	12	18	A-	17.2
2011	Dallas Keuchel	Pitcher	4Yr	26	23	AA	12.0
2012	Dallas Keuchel	Pitcher	4Yr	17	21	AAA	14.2
2006	Dan Uggla	Position Player	4Yr	2	29	AA	20.3
2003	David Bush	Pitcher	4Yr	6	14	A+	10.1
2003	David DeJesus	Position Player	4Yr	26	19	AA	13.6
2013	Dellin Betances	Pitcher	HS	11	19	MLB	11.2
2014	Dellin Betances	Pitcher	HS	18	26	MLB	11.3
2005	Denard Span	Position Player	HS	4	14	A	10.0
2007	Denard Span	Position Player	HS	8	13	AA	15.1
2008	Denard Span	Position Player	HS	18	20	AAA	18.3
2002	Dontrelle Willis	Pitcher	HS	1	21	A-	20.8
2001	Erik Bedard	Pitcher	JC	27	19	A	10.5
2005	Freddy Sanchez	Position Player	4Yr	18	13	MLB	14.9
2006	Geovany Soto	Position Player	HS	15	16	MLB	12.6
2007	Geovany Soto	Position Player	HS	18	17	MLB	13.8
2015	German Marquez	Pitcher	INTL	17	25	A	13.3
2008	Ian Desmond	Position Player	HS	9	14	AA	10.7
2009	Ian Desmond	Position Player	HS	21	19	AA	14.8
2013	Jake deGrom	Pitcher	4Yr	26	11	A+	26.2
2006	Jamie Shields	Pitcher	HS	10	12	AAA	20.3
2003	Jason Bay	Position Player	4Yr	20	12	AA	15.9
2004	Jayson Werth	Position Player	HS	8	17	MLB	16.6
2008	Jonathan Lucroy	Position Player	4Yr	21	16	Rk	22.4
2004	Jonathan Papelbon	Pitcher	4Yr	23	14	A-	10.2
2011	Jose Altuve	Position Player	INTL	26	28	A+	19.0
2013	Jose Ramirez	Position Player	INTL	24	23	A	21.0
2009	Josh Donaldson	Position Player	4Yr	3	13	A+	13.9
2010	Josh Donaldson	Position Player	4Yr	12	14	AA	22.6
2011	Josh Donaldson	Position Player	4Yr	28	12	MLB	30.5
2012	Josh Donaldson	Position Player	4Yr	26	20	MLB	35.6
2007	Josh Hamilton	Position Player	HS	12	30	AA	25.2
2004	Josh Johnson	Pitcher	HS	14	24	A	10.8
2005	Josh Johnson	Pitcher	HS	14	11	A+	16.4
2006	Josh Willingham	Position Player	4Yr	2	11	MLB	13.3
2007	Justin Masterson	Pitcher	4Yr	9	13	A-	12.2
2010	Kenley Jansen	Pitcher	INTL	24	14	AAA	10.9
2014	Ketel Marte	Position Player	INTL	25	20	A+	11.6
2011	Kevin Kiermaier	Position Player	JC	3	26	Rk	11.1
2013	Kevin Pillar	Position Player	4Yr	12	21	A+	10.3
2014	Kevin Pillar	Position Player	4Yr	15	20	MLB	11.9
2013	Khris Davis	Position Player	4Yr	22	16	AAA	11.5
2012	Kole Calhoun	Position Player	4Yr	18	20	A+	13.1
2013	Kole Calhoun	Position Player	4Yr	30	11	MLB	13.1
2014	Kyle Hendricks	Pitcher	4Yr	4	11	AAA	18.0
2010	Kyle Seager	Position Player	4Yr	11	30	A+	17.6
2015	Lance McCullers	Pitcher	HS	10	11	A+	10.7
2005	Luke Scott	Position Player	4Yr	22	17	AA	11.1
2006	Luke Scott	Position Player	4Yr	20	15	MLB	11.3
2001	Mark Ellis	Position Player	4Yr	11	17	AA	10.7
2003	Mark Hendrickson	Pitcher	4Yr	6	13	MLB	10.5
2003	Matt Cain	Pitcher	HS	11	11	Rk	11.8
2011	Matt Carpenter	Position Player	4Yr	24	11	AA	20.5
2012	Matt Carpenter	Position Player	4Yr	12	12	MLB	23.8
2002	Matt Holliday	Position Player	HS	24	11	A+	14.3
2003	Matt Holliday	Position Player	HS	25	16	AA	20.2
2015	Max Kepler	Position Player	INTL	2	12	A+	10.8
2014	Mike Clevinger	Pitcher	JC	30	17	A	10.8
2015	Mike Clevinger	Pitcher	JC	23	22	A+	11.5
2005	Mike Napoli	Position Player	HS	1	29	A+	10.0
2006	Mike Napoli	Position Player	HS	3	11	AA	14.3
2008	Mike Stanton	Position Player	HS	14	11	A-	14.7
2001	Morgan Ensberg	Position Player	4Yr	10	15	MLB	15.4
2010	Neil Walker	Position Player	HS	16	26	MLB	15.9
2003	Nick Swisher	Position Player	4Yr	22	11	A+	11.2
2011	Noah Syndergaard	Pitcher	HS	4	24	Rk	10.0
2012	Odubel Herrera	Position Player	INTL	2	27	A	10.4
2015	Odubel Herrera	Position Player	INTL	22	12	AA	10.9
2006	Pablo Sandoval	Position Player	INTL	18	15	A-	12.6
2010	Paul Goldschmidt	Position Player	4Yr	27	13	Rk	20.9
2011	Paul Goldschmidt	Position Player	4Yr	22	11	A+	25.8
2002	Rich Harden	Pitcher	JC	19	21	A-	10.2
2005	Ricky Nolasco	Pitcher	HS	10	19	AAA	11.9
2013	Robbie Ray	Pitcher	HS	16	18	A+	10.2
2015	Robbie Ray	Pitcher	HS	6	11	MLB	11.8
2004	Russell Martin	Position Player	JC	2	18	A	18.9
2009	Ryan Hanigan	Position Player	4Yr	14	16	MLB	16.5
2002	Ryan Howard	Position Player	4Yr	11	15	A-	11.6
2004	Scott Baker	Pitcher	4Yr	5	19	A	10.7
2005	Shane Victorino	Position Player	HS	20	19	MLB	16.4
2006	Shane Victorino	Position Player	HS	22	14	MLB	21.9
2001	Ted Lilly	Pitcher	JC	7	18	MLB	10.4
2014	Tommy Pham	Position Player	HS	7	23	AAA	15.6
2015	Tommy Pham	Position Player	HS	15	15	MLB	15.5
2001	Travis Hafner	Position Player	JC	13	12	A+	16.1
2002	Travis Hafner	Position Player	JC	8	16	AA	18.3
2013	Travis Shaw	Position Player	4Yr	6	23	AA	10.0
2015	Trevor Story	Position Player	HS	8	12	AA	17.9
2011	Tyler Flowers	Position Player	JC	27	17	MLB	11.0
2008	Will Venable	Position Player	4Yr	12	15	AA	11.5
2013	Yan Gomes	Position Player	4Yr	24	27	MLB	13.6
2005	Yovani Gallardo	Pitcher	HS	3	16	A	11.5
2004	Zach Duke	Pitcher	HS	11	15	A	12.6

The first thing that stands out is that there are far more position players than pitchers. I do not know for certain why this is the case, but I have several theories. The first is that pitchers are fragile by nature and they are more likely to be injured and unable to generate as much WAR as position players. Another theory is that it may be easier to scout pitchers than position players and that the more successful pitchers are ranked higher and are excluded from my dataset.

Another observation is that almost half of the players attended college and there are relatively few international players that achieve stardom. Of the 97 players in my dataset, forty-five of them attended a four-year university and there are only eleven international players. However, his does not necessarily mean that college players are more likely to exceed their prospect ranking.

From 2001 through 2015, over 40% of players that were ranked between eleven and thirty in their organization attended college. This is the most prevalent type of amateur experience by far. It stands to reason that they would have more people accrue 10 or more WAR.

It appears that international players are less likely to reach 10 WAR. There is roughly the same amount of ranked high school and international players, but there are 30 high schoolers that reached 10 WAR compared to only 11 international players. I do not really have a good explanation for this phenomenon, but I do find it interesting.

The final observation I have is from the position player bar chart. I find it interesting that players with AAA as their highest level are the least represented group. The only explanation I can offer is that perhaps players that reach AAA but not the Majors are perceived as having lower ceilings and their teams decided they were not worthy of being called up in September when rosters expanded. This could artificially lower the AAA group and increase the size of the MLB group. If rosters did not expand in September, I think that there would be far more players in the AAA group and fewer in the MLB group.

Conclusions

Most prospect value is concentrated in the top of a team’s farm system, but value can come from any ranking position.
Position players are more likely to outperform their ranking than pitchers.
College position players are the most prevalent lower ranked prospects to accrue 10 or more WAR.
International players are the least likely to generate 10 or more WAR.

Evaluating prospects is a difficult endeavor and I hope that this article helps to illuminate the types of players that are typically overlooked by prospect evaluators.

Click here for GitHub code

An Examination of Rebuilding Team Timelines

Rebuilding has become the popular way for MLB franchises to build a perennial World Series contender. With the league’s structure of compensating the worst teams with the best draft picks, it seems like a viable strategy to maximize your losses in order to obtain the services of the best amateur talent available. The Astros and Cubs are two of the more recent franchises to successfully cap their extensive rebuilding process with a World Series victory. Both franchises acquired top ten draft picks for several years before they turned the corner and became World Series contenders, but how often does this strategy work and how long does a rebuild take?

If an organization’s strategy is to not win games right away, when do the fans and ownership realize that the rebuilding process has failed and that their team is in the middle of a downward spiral of ineptitude? I am sure there are fans of the Pittsburgh Pirates and Kansas City Royals from the 1990s and 2000s that know how difficult it is to build a contender and cringe whenever they hear the term rebuild. Hopefully, this article can provide a reasonable timeline for contention and an objective overview on how a franchise’s rebuilding effort should be progressing.

For my dataset, I gathered the GM or President of Baseball Operations for each organization since 1998. I chose 1998 because it was the first year the league consisted of 30 teams and it also happened to be the first full season for the current longest tenured executives Billy Beane and Brian Cashman. If an executive’s tenure with the team started before the 1998 season, their entire tenure was included in the dataset. So, the Braves GM John Schuerholz’s regime is measured in its entirety from 1991-2007 and not just from 1998-2007.

For executives that took over an organization during the regular season, I credited the team’s record from the executive’s first full season of running baseball operations and not the partial season they assumed their duties. For example, the 2002 Detroit Tigers record goes on Randy Smith’s ledger instead of Dave Dombrowski even though Dombrowski took over one week into the regular season.

To determine which front offices inherited a rebuiling situation, I limited the dataset to teams that had a winning percentage lower than .432 the year before the new executive assumed leadership. I chose a .432 winning percentage, because this corresponds to a team that failed to win 70 games in a 162 game season. Most organizations that lose this many games in a season realize that they likely have a long time before contention and that a rebuild is necessary. By choosing such a low win threshold, I eliminate several rebuilds like the Theo Epstein led Cubs, but I’d rather exclude several rebuilds than include 70 win teams that just had an off year and returned to prominence using the same core players.

I decided to include the new expansion team front offices, since they are starting a new organization from scratch I feel they firmly belong in the rebuilding category. This leaves me with 40 different rebuilds to analyze and nine of them are current regimes. Below is a summary of each rebuild with the current front office leaders highlighted.

Seven different regimes won at least one World Series and 23 of the 40 front offices had at least one postseason appearance. The longest tenure without a playoff appearance is a tie for eight seasons between the Chuck LaMar led Tampa Bay Devil Rays and the Ed Wade led Philadelphia Phillies.

Next, I wanted to inspect how each administration’s winning percentage progressed by season. I created a boxplot of each team’s winning percentage by the executive’s season in the organization. I decided to stop the x-axis at eight seasons, because that is the longest time that an executive kept his job without making the postseason. It is also the first season where over 50% of the front offices had been replaced, so it seemed like a reasonable stopping point. I also added a summary table of when each front office accomplished certain goals by season.

The median for winning percentage increases each season. There are likely two reasons for this event. The first is that any team that initiates a rebuild is at or near the nadir of their suffering and there is nowhere to go but up. The second is that there is a survivor bias. A front office that is underperforming expectations is more likely to be replaced and those teams do not appear in the boxplot to drag down the winning percentage calculation.

I find it interesting that the median for season four performance is exactly .500. This appears to be the make-or-break season for if a rebuild is deemed a failure or a success. Out of the 23 administrations that eventually made the playoffs, only five made the postseason for the first time after their fourth full season running baseball operations. However, it is worth mentioning that two of these regimes did eventually win the World Series. The Dave Dombrowski led Florida Marlins won in his fifth full season at the helm and the Dayton Moore led Kansas City Royals won the Pennant in his eight full season and the World Series in his ninth full season. These two cases provide hope for slower developing rebuilds, but most rebuilds can be considered a failure after four seasons if there has been no significant progress at the Major League level.

Of the nine current administrations that inherited a rebuilding team, there are only two administrations that have not made the postseason. The Pittsburgh Pirates and the Baltimore Orioles. They also happen to be the only two teams that have not reached the critical fourth season. Only time will tell if these rebuilds will be considered a success, but they both still have a long way to go, and the clock is ticking.

Click here for GitHub code.

Is Consistent Contact More Important than Raw Power?

There are many types of hitters that have had success in baseball history. There are hitters with light-tower power like Giancarlo Stanton and players with exceptional bat control like Tony Gwynn or Ichiro Suzuki. Not many people can hit the ball as hard as Giancarlo Stanton, so many coaches and advisors instruct their players to focus on hitting the ball hard consistently instead of maximizing their power output. Is this good advice? Is it possible that consistent hard contact can overcome a player’s power deficiency?

To answer this question, I collected batted ball data from the 2019 and 2020 seasons from Baseball Savant and found each batter’s maximum exit velocity. I am working under the assumption that a player’s maximum exit velocity is a suitable facsimile for raw power. I then tabulated how many times a player’s exit velocity was within 90% of his maximum exit velocity and divided it by the batted balls put in play that registered an exit velocity reading. I call this new stat exit velocity efficiency. I chose the 90% threshold, because the lowest maximum exit velocity readings in the Majors for qualified hitters is around 100 MPH and I believe that 90 MPH is the lowest reasonable threshold for what qualifies as a hard-hit baseball. Next, I limited the dataset to include players that have had over 100 batted ball events combined between the 2019 and 2020 seasons. This left me with 449 Major Leaguers to analyze.

The first thing I wanted to do was compare a player’s exit velocity efficiency and his maximum exit velocity to a performance metric to help determine which statistic has a stronger relationship with hitting performance. I believe that wOBACON is the best option for a performance metric, because it focuses solely on balls in play. I am choosing to ignore other factors like plate discipline and contact rate for simplicity, but these are important aspects of hitting that I will explore later.

These scatter plots show that there is a far stronger relationship between maximum exit velocity and wOBACON than there is between exit velocity efficiency and wOBACON. The former has a Pearson correlation coefficient of 0.55 and the latter has a 0.03 Pearson correlation coefficient indicating almost no relationship at all.

Why is the relationship so low for exit velocity efficiency? It is because players with exceptional raw power do not need to consistently hit balls over 90% of their maximum exit velocity to be effective. Someone who can hit the ball over 118 MPH, like Aaron Judge, have a far greater margin for error for their batted balls than someone like Billy Hamilton who has difficulty reaching 100 MPH. Since exit velocity efficiency is based on each player’s individual maximum exit velocity, it makes sense that players with different maximum exit velocities and similar exit velocity efficiencies would have vastly different batted ball results.

For example, Mookie Betts and Tony Kemp both have an exit velocity efficiency of 33%, but Mookie Betts has a maximum exit velocity of 109.3 MPH compared to Tony Kemp’s 101.4 MPH. Kemp’s wOBACON registers a .299 while Betts has a more robust .428. This is all just a long way of saying that exit velocity efficiency on its own does not have a strong correlation with batted ball success.

Even though maximum exit velocity has a strong relationship with wOBACON, there are still several players that do not possess elite power that are highly effective hitters and there are some hitters who have power but are not the most productive hitters. A great hitter needs to have both power and efficiency, but one usually comes at the expense of the other. What is the best ratio to maximize a player’s performance? Is there a way to identify and classify these players to help them realize what style of hitting works best for them?

K-Means Clustering

I decided to use a machine learning technique called k-means clustering to group the players by their maximum exit velocity and efficient exit velocity readings to determine which hitting approach produces the best results on average. I found that there are five distinct groups of hitters and each group’s mean performance can be found in the table below along with the cluster plot and a review of each group’s results.

Group 5 – Great Power, Below Average Efficiency

This is the most successful group on average and they represent players with the most power. They trade some exit velocity efficiency for power, but their power helps overcome their lack of efficiency in general. This group has the highest wOBACON, wOBA, and wRC+ on average, but a density plot will provide more information as to the distribution of talent. Since each group’s order of success is the same regardless of which offensive metric being chosen, I will be using wRC+ for each density plot moving forward. The metric is easier to interpret and it incorporates more aspects of hitting than batted ball outcomes alone.

There appears to be some risk in this group with many players performing below the mean value. It seems that the extraordinary hitters are propping up the group’s wRC+ average, but there are plenty of players that have issues making consistent contact dragging down their overall value. Players like Mike Zunino and Gregory Polanco have good wOBACON numbers, but their swing and miss issues are too much to overcome to be considered good hitters.

Group 2 – Good Power, Good Efficiency

This group represents the players that do not have top of the scale power but make up for it by being more efficient in their contact quality. The top performers in this cohort are players that can combine their contact abilities with exceptional plate discipline like Juan Soto and Freddie Freeman.

This group has a higher distribution of good hitters, but they do not have the top tier talents to raise the mean wRC+ that the previous group did. This group may not have as much upside, but the floor appears to be a bit higher than the Group 5 hitters.

Group 4 – Great Efficiency, Just Enough Power

Group 4 has a much lower maximum exit velocity than the previous two groups, but they are by far the most efficient group. The hitters that have success in this group are players like Alex Bregman and Anthony Rendon. Bregman and Rendon consistently elevate the ball and limit their swings and misses. Therefore, their profile is effective even though they have a lack of raw power.

This is the first distribution chart where the peak is below 100 wRC+ and it shows how difficult it is to be a great hitter without big raw power. It is still possible, but the margin for error is much finer.

Group 1 – Good Power, Below Average Efficiency

This group is the first to have a below average wRC+ collectively. They also may be the most frustrating. Group 1 is full of players that have comparable raw power to Group 2, but not Group 2’s efficiency.

Group 1 may be the most frustrating, but they are also the most tantalizing. Group 1 hitters have the raw tools necessary for success and it is possible that with more seasoning and a refined approach they could improve their efficiency and become more like the hitters in Group 2.

Group 3 – Good Efficiency, Not Enough Power

This final group is littered with players that rely more on their defense and versatility than their bat to provide value to their club. Players like catchers, middle infielders, and fourth outfielders. Group 3 has the lowest wRC+ and it seems that most of these players lack the physical strength needed to be considered an elite hitter.

This group may have the worst results overall, but all hope is not lost for this type of hitter. Jeff McNeil, Tim Anderson, and Marcus Semien have all recorded a WRC+ over 120 over the last two seasons, so it is possible to succeed with this profile.

Conclusion

My cluster analysis shows that it is possible to be a successful Major League hitter as a member of any group, but it is clearly beneficial to have the ability to hit the ball hard. Both raw power and efficiency are essential to hitters, but if I had to choose which is more important to a hitter’s success, I would choose raw power. Consistent contact is useful, but if a player’s raw power does not meet a certain threshold there is little chance that he will be a productive Major League hitter.

Click here for GitHub code.

Using Bayesian Models to Predict MLB Free Agent Salaries

Executive Summary

I created a linear regression model to predict how much salary a Major League player will make in free agency. This model will help determine which free agents are affordable and fit into the team’s yearly budget. I used a player’s WAR values from the previous three seasons, All-Star and MVP status, position, and contract length to predict his salary. I found that players that sign one-year deals or deals that are seven years or longer have lower intercept values than players that sign for two to six seasons. Pitcher’s also command higher salaries for the same performance compared to their position player counterparts.

Introduction

The purpose of this model is to predict the salary a Major League baseball player will earn in free agency. Major League teams work under a budget built on player salary and this model will help to identify which players can be signed to improve the team’s chances of winning without going over their yearly budget. I will create a model that uses on-field performance as well as career awards and honors to predict the player’s salary.

Data

The data were collected from ESPN’s MLB Free Agent Tracker, FanGraphs.com and Baseball-Reference.com and it includes any player that signed a Major League contract from the 2006 to 2019 off-season. The model will be predicting the dollar amount the player signed for in present value divided by the length of the contract. Major League Baseball salaries have continued to increase every year and I believe that it would be easier to model the present value salary instead of introducing another variable into the model to control for the year the player signed his contract. I decided to use a 3% inflation rate and it seems to be a good facsimile for annual salary in 2020 terms.

I obtained the WAR values from the player’s previous season and the two years prior from both FanGraphs and Baseball-Reference and averaged them together to create two new columns called MixedWAR_1 and MixedWAR_2. WAR is a comprehensive metric used to gauge the overall on-field value a player provided to his team. FanGraphs and Baseball-Reference have similar methodologies, but there are slight differences in the way the stat is calculated that can create a discrepancy for the overall value a player generated for his team. Therefore, I decided to average the two values together into one column. I decided to separate the most recent season from the other two seasons, because the most recent season is more predictive of a player’s future performance than what a player produced three seasons ago. This could be due to either injury, aging or a change in skill level from one season to the next.

The next thing I wanted to account for other than on-field performance was a player’s perceived value. A team will sometimes pay a player more for their past accomplishments and perceived upside than a player who has produced similar value over the last several years. I attempted to simulate this effect with two categorical variables called MVP_Candidate and All_Star. If a player ever played in an All-Star game or received an MVP vote, they were counted as a yes in these categories.

The last variable I decided to account for was if the player was a hitter or a pitcher. These two positions have different jobs, and it is quite likely that they are compensated differently. Pitchers are more prone to injury, but they are also in higher demand, because they are easier to find playing time for than position players.

There were not too many challenges in collecting the data for this project since Major League Baseball is skilled at checking their data. The only thing I needed to do was omit any player that had signed to play in a different league or anyone that played in a different league but had not played in the Majors in the previous season. I excluded these players, because I do not think it would be fair to include a player’s statistics from another league as Major League statistics or to completely ignore their on-field production in a less competitive league and give them a zero for the previous year’s WAR value. If a team wants to sign a player that is coming from a different country’s league, this model will not apply to them.

I plan on using a linear regression model, but first I need to see what distribution would be appropriate for my predicted values. Below is the histogram of a player’s present value salary.

Clearly the data is right skewed, so using a standard normal distribution would not be an appropriate choice. Perhaps transforming the values using the logarithmic function will give a more normal distribution.

This is much better. Going forward I will be using this transformed column as my dependent variable.

Model

In the first model I decided to use the same non-informative prior that we used in the class example with all betas following a standard normal distribution (0, 1000000) and a precision that follows a gamma distribution (2.5,25) and a likelihood function of

Y_{i =}β₁ + β₂*MixedWAR_1_i+ β₃*MixedWAR_2_i+ β₄*MVP_Candidate_i+ β₅*All_Star_i+ β₆*Pitcher_i

that follows a standard normal distribution. I chose non-informative priors, because I did not have any preconceived notions of what the distribution should look like.

This model should be appropriate now that I have transformed my response variable to better resemble a standard normal curve and the WAR parameters approximately follow a standard normal curve and the other variables in the model are explanatory variables. Each of these parameters should help to identify how much of a raise to expect in salary when WAR is increased as well as how much value making an All-Star game or appearing on the MVP ballot is worth. This model accounts for on-field performance as well as career accomplishments and should be able to reasonably predict a player’s salary for the upcoming season.

All the parameters in the model converge and there is minimal autocorrelation. The residual plot looks random and the normal QQ plot looks like a reasonably straight line, although the model does seem to have a little trouble with extreme outliers. The model does seem to have trouble overestimating the salary of high performing players. This may be because many top performers take longer term deals that artificially lower their salary but guarantees more money overall. The baseball industry usually makes these deals because it lowers the player’s salary, and this allows the signing team to have more flexibility to stay under the luxury tax threshold while the player gets greater security even when his performance starts to suffer. The DIC for the first model is 2461.

I will attempt to account for these longer-term deals by creating a hierarchical model that creates groups based on contract length. Group 1 will be for one-year deals, Group 2 will be for two-year deals, Group 3 will be for three to four-year deals, Group 4 will be for five to six-year deals and Group 5 will be for deals that are seven years or longer. All the parameters in the model converge and there is minimal autocorrelation. The residual plot looks random and the normal QQ plot looks like a reasonably straight line, however the model does seem to still have trouble with extreme outliers, but the DIC has decreased to 2219 which means that the newer model is superior.

Results

The mean coefficients for the model are as follows:

Intercept for 1-year deals = .45

Intercept for 2-year deals = .90

Intercept for 3-4-year deals = 1.12

Intercept for 5-6-year deals = .94

Intercept for 7 or more-year deals = .35

Coefficient for previous season’s WAR = .20

Coefficient for previous two season’s WAR = .09

Coefficient for MVP candidate = .03

Coefficient for All-Star appearance = .13

Coefficient for being a pitcher = .23

These coefficients show that pitchers receive a sizable bump in salary compared to position players, and surprisingly that an All-Star appearance is worth more than being an MVP candidate. The model also shows that length of the deal has a huge impact on a player’s salary. As expected, longer term deals have a lower coefficient, but one-year deals are quite low as well. This is probably because many players that secure one-year deals are bench players that do not command as much salary and teams are not willing to commit to bench players for multiple years and this could be the reason why the intercept is so low. This probably means that the model will underestimate prominent older players who sign one-year deals not due to a decrease in performance, but because they are close to retirement and do not desire a long-term deal. If I could improve the model, I would probably exclude any deal over seven years to try and eliminate some of the skew in the response variable.

Click here for GitHub code.

How Much Value is Really in the Farm System?

Everyone knows that a strong farm system is the key to the long-term success of a Major League organization. What team would not want all-star players at below market rates? These players make it possible for organizations to field competitive teams and stay beneath the luxury tax threshold, but how much value can an organization expect from their farm system? How much more value do the best farm systems generate compared to the worst farm systems? These are some of the questions I attempted to answer with this article.

Methodology

The first thing I did was gather the player information and rankings from the Baseball America’s Prospect Handbooks taking place from 2001 to 2014 and entered them into a database. I then found the player’s total WAR (from FanGraphs.com) produced over the next six seasons and added them together to find the value the farm system produced. I chose six seasons to ensure that no team would get credit for a player’s non-team-controlled seasons, since the value produced in the following seasons would not be guaranteed for the player’s current organization. This method will reduce the total value produced by players that are further away from the Majors, but the purpose of this analysis is to focus on the value of the entire farm system and not an individual player’s value over the course of their career.

I believe that an example will help to understand my methodology, so let us look at the 2014 Minnesota Twins farm system. Below is a list of the thirty players that were ranked and the amount of WAR that each player produced by season.

In this table, we can see that the 2014 Minnesota Twins farm system produced 70.1 WAR over six seasons with 26.9 WAR coming in 2019. I repeated this process for every team to create my dataset.

Total WAR Produced by Farm System

The first thing I wanted to examine was how much total WAR an organization could expect from their farm system. To do this, I calculated the mean of WAR produced for each farm system and found that the average was 45.83 WAR produced over six seasons. I also discovered that the maximum WAR for a farm system was produced by the 2003 Cleveland Indians with a total of 136.0 WAR and the minimum value came from the 2008 Seattle Mariners with a total of -1.7 WAR.

The next thing I wanted to examine was the distribution of WAR values. Do they follow a standard normal distribution or is something else going on? Below is a density plot of all farm system’s WAR over six seasons.

There is nothing too crazy going on here, but it looks like the distribution is positively skewed with the 2003 Cleveland Indians as an outlier with 23.6 WAR more than the next highest organization. I am not surprised that the data is skewed, because if a player is doing well, he will accumulate more playing time and WAR. However, if a player is not performing well, he is in danger of being sent down to the Minor Leagues. This makes it difficult for the left tail to mirror the right tail distribution.

WAR Produced by Farm System in a Single Season

The amount of WAR generated over six seasons is a good way to show the overall production and general well-being of an organization’s farm system, but I believe it is just as important to see how much WAR an organization can generate in a given season. Producing 45.0 WAR over six years is the average, but how did you distribute them? If your farm system does not produce any WAR for the first five years, but produces 45.0 WAR in year six is that better than producing 7.5 WAR in six consecutive seasons? If you are the GM of a 100-loss club, you may prefer the 45.0 WAR in a single season, since 7.5 WAR in a season will probably not get you into the postseason. If you are the GM of a contending team, you may want the 7.5 WAR a year instead, since your team is already competing for a playoff spot every year. So how much WAR can you expect from a farm system in a single season?

Once again, I calculated the mean WAR value, but this time I found it for each individual season. The mean value was 7.64 WAR with a maximum of 31.7 WAR by the 2003 Cleveland Indians farm system in 2005. The minimum was the 2008 Seattle Mariners farm system which produced -7.4 WAR in 2010. The density plot is shown below.

Once again, we see a positively skewed distribution, but there is something else that I would like to account for before moving forward. To create this visual I compiled seasons one through six for each farm system and treated all seasons equally, but that may not be the best way to interpret the data. The next visual shows the distributions for each individual season in relation to the year of the organization’s ranking. So, in our 2014 Minnesota Twins example the WAR produced in 2014 would be in the distribution labeled “Same Season”. The 2015 season would be in the distribution labeled “Second Season” and so on and so forth to the “Sixth Season” distribution.

The visual shows us that we should not treat all seasons as equal. The first season distribution is vastly different from the others with almost 20% of players hovering around 0.0 WAR produced in a season. The second and third season distributions are not as stark as the same season distribution, but these distributions are not like the distributions for seasons four through six. This makes sense, since many of the prospects appearing in the Prospect Handbook are not perceived to be ready for the Majors any time soon. I believe that it would be more beneficial for my individual season analysis to only look at seasons four through six to determine how much WAR a team can expect from its farm system.

WAR Produced by Farm System in a Single Season (Years 4-6)

Without Seasons 1-3 the mean moves up to 10.3 WAR and the distribution appears a little less skewed. This is a decent way to look at the data, but it is only looking at one variable. How can we account for the different quality of farm systems? This is where Baseball America’s team rankings come into play.

Total WAR Produced by Farm System Ranking

Every season Baseball America ranks MLB’s farm systems from one to thirty with one being the most talented farm system and thirty being the least talented farm system. It is obviously beneficial to be closer to the top ranking, but how much more valuable is a top-tier farm system compared to the bottom or an average farm system? The graphic below is an attempt to answer this question.

This graph was created by looking at the total WAR produced by a farm system in six years according to their team ranking in Baseball America. That means that there are fourteen data points for each box plot. I decided to use box plots for each ranking instead of looking at the mean or median, because I wanted to highlight how much variance there is for each ranking.

I also added a blue trend line to show the general relationship between team ranking and WAR. The blue line shows that WAR goes down as team ranking gets closer to thirty. It also looks like the trend line for rankings one through ten is steeper than the rest of the rankings. This means that moving from the tenth ranked system to the first ranked system has a much larger impact on WAR than moving from the twentieth ranked system to the tenth ranked system.

Single Season WAR Produced by Farm System Ranking

Once again, I thought it would be interesting to look at single season WAR produced by a farm system. I excluded seasons one through three for the same reasons mentioned earlier. Below is the same box plot chart, but for individual season WAR instead of WAR produced over six seasons.

The blue line shows that WAR goes down as team ranking gets closer to thirty, but it also appears that the trend line is more linear than the trend line in the previous chart. I am not sure why this is happening, but I do find it interesting that a single season of WAR is linear, but six seasons of WAR is not.

Conclusions

The most WAR produced by a farm system over six years was the 2003 Indians with 136.0 WAR. The second most was the 2006 Marlins with 112.4 WAR. The Indians were such an outlier that teams and fans should probably not expect more than 110.0 WAR from their farm system no matter how good their farm system appears.
The average WAR produced by a farm system over six years is 45.83 WAR.
The most WAR produced in a single season was in 2005 with 31.7 WAR from the 2003 Cleveland Indians farm system. This means that teams and fans should not expect much more than 30.0 WAR from their farm system in any given year.
Seasons one through three for a farm system have vastly different distributions than seasons four through six. This means that teams and fans should not expect their farm system to be productive right away and that they should not be judged too harshly in the first three seasons.

Data Acknowledgments

All the player information was obtained from Baseball America Prospect Handbooks and all the WAR figures were obtained from FanGraphs.com.

Click here for GitHub code.

Analyzing the Draft

Ever since the Major League Draft was created in 1965, teams have been searching for any competitive edge possible to separate themselves from the rest of the league. It is after all one of the best ways to acquire young affordable talent for your organization. Not picking the best player available is a huge missed opportunity for any club and it can set the organization back for years. It can also exasperate even the most devoted fans. Therefore, it is imperative to have successful drafts every year, but what constitutes a successful draft? How many Major Leaguers are available in a draft and where can you find these players? These are some of the questions I hope to answer in this article.

Methodology

Much of my analysis in this article will include references to team-controlled WAR. I calculated each draftee’s WAR total by summing their pitching and hitting WAR totals for the first seven years of their career to estimate the amount of value the players provided their clubs before the players were eligible for free agency. This method is not perfect, because it does not consider demotions to the minor leagues and it incorrectly assumes that every team would keep their prospects down in the minors to gain an extra year of control. However, I believe that the first seven years of WAR in a player’s career is a valid estimation of the value a player provides his organization before he exhausts his team-controlled seasons.

The drafts being examined are the drafts that took place from 1965 to 2004. I chose to stop at 2004, because that was the last year that had every player in its draft class exhaust his team-controlled seasons. If I were to include more recent drafts that still have active players, I could draw erroneous conclusions, since these players still have time to make their Major League debuts and accumulate more WAR in their team-controlled seasons.

MLB Players Drafted by Year

The graph below shows how many eventual Major Leaguers were drafted every year. This dataset includes all players that were drafted whether they signed with their team or not. So, it does include duplicate values for players that were selected more than once. I decided to keep these duplicates, because I wanted this graph to show the total amount of Major Leaguers available in each draft class and if a player didn’t sign with his team the player would still be eligible for the next year’s draft.

The main thing that jumps out is the increase in Major League players starting in 1987. Major League Baseball used to have a January draft and two secondary drafts that took place in June and January and 1987 was the first year where the league consolidated all the drafts into one. This is likely the main reason for the dramatic increase in Major Leaguers selected. I also believe that the number of Major Leaguers increased due to expansion. Major League Baseball increased from 26 teams in 1987 to 30 teams in 1998 and this means that the league created more opportunities for drafted players to occupy those newly created roster spots.

Available WAR by Draft Year

The next thing I chose to investigate was the amount of WAR available every year. It is nice to know how many Major Leaguers are drafted each year, but it is more important to find how much value is available each draft. What would you rather have your team do, draft one All-star talent or three up and down relievers? The previous chart ignored the value created by these Major Leaguers, while the chart below shows how much total WAR was available in each draft class. I once again included players that were drafted more than once for the same reason listed above.

The draft year with the most available WAR was 2002 with 737.1 followed by 695.6 WAR in 1982 and 665.1 WAR in 1981. The draft year with the lowest WAR total was 1975 with 317 WAR followed by 1970 with 332.1 WAR and 1971 with 339.1 WAR.

The 2002 draft had plenty of high profile first round picks like Cole Hamels, Zack Greinke and Prince Fielder, but even more impressive was the overall depth of Major League All-stars available that year. Brian McCann, Joey Votto and Jon Lester were all selected in the 2^nd round and they each contributed over 20 WAR in their team-controlled seasons. Russell Martin was drafted in the 17^th round and Jacoby Ellsbury and Matt Garza were both selected out of High School but chose not to sign with their teams.

The 1982 draft featured Barry Bonds, Dwight Gooden, Bret Saberhagen, Will Clark, Barry Larkin, and Jose Canseco and each of them produced over 25 WAR in their team-controlled seasons with Barry Bonds leading the way with 48.4 WAR.

The 1981 draft had eight players produce over 25 WAR and were headlined by Roger Clemens with 43.7 WAR out of San Jacinto College. He was selected by the New York Mets in the 12^th round, but he did not sign and went to the Red Sox in the first round two years later. Can you imagine the 1986 Mets rotation if they had signed both Clemens and Gooden?

The 1975 draft was not devoid of talent with Andre Dawson, Lou Whitaker and Lee Smith all being drafted, but Dawson was the only player that produced over 25 WAR with Lou Whitaker and Jason Thompson coming in second and third with 22.4 and 22.3 WAR. There were a few other Major League contributors in this draft class, but the depth of this year’s draft class just was not there.

Available WAR Bucketed for each Draft Year

The information above only shows the total amount of WAR, but the distribution of WAR matters as well. For example, if there are two draft classes with a total of 300 WAR each and one is produced by 10 players and another is produced by 30 players. A team that selects later in the draft would probably prefer to pick in the class that has 30 players, since their odds of selecting some type of Major League contributor are higher than the year with only 10 players.

The table below will be grouping drafted players by 5 WAR increments to show the number of players available in each grouping by draft year. I also replicated the table showing the percentage breakdown for each year as well to account for the different sizes in draft classes.

There is a lot to unpack here. The first thing we will examine is the overall success rate of MLB draft picks. There have been 45,694 total draft picks through 2004 and 6,459 of those eventually made it to the Majors. That means that 85.86% of draft picks never appeared in a Major League game. Of all the draft picks made, 44,325 of them did not produce more than 5 WAR in their team-controlled seasons. That means 97% of all draft picks produced less than 5 WAR in their team-controlled seasons.

The next thing that stands out is the minimal number of star-level players that are available in each draft. On average there are only 3.15 players available each year that produce 25 or more WAR in the Majors. The year with the most of these players was in 1981 with eight and 1974 was the only year that did not have any players produce 25 or more WAR.

The main take away from these tables is that it is extremely difficult to make it to the Major Leagues and even more difficult to produce at a high level. It is no surprise that it is extremely difficult for teams to build a championship caliber roster through the draft alone. Which brings me to the next part of my analysis.

Best Draft Classes of All-time

The draft is paramount to any organization’s long-term success. Being able to consistently choose future Major Leaguers to replenish an organization’s depth ensures that a team can compete for championships year in and year out. A successful draft can also launch a losing team into contention, but what constitutes a successful draft? The chart below answers this question by showing the teams that drafted the most WAR in a single season. The dataset used for the chart excludes any players who did not sign with their drafting team. If I included players who refused to sign with their team, I would be rewarding teams that drafted players when they had no intention of meeting the player’s asking price to forgo his amateur career.

The team with the most WAR was the 1976 Boston Red Sox with 79.1 WAR followed closely by the 1999 Cardinals with 76 WAR and the 1989 Twins with 75.4 WAR. These teams obliterated the Major League average draft class of 14.26 WAR and the median value of 10.9 WAR.

The 1976 Red Sox draft class had a total of seven Major Leaguers with three players producing over 10 WAR each. Bruce Hurst produced 12.5 WAR and Mike Smithson produced 12.3 WAR, but the heavy lifting was done by seventh round draft pick Wade Boggs. Boggs produced a whopping 51.7 WAR in his first seven seasons which is the second most ever by a player drafted from 1965 to 2004. The only player to produce more team-controlled WAR over this period is mentioned in the next paragraph.

The 1999 Cardinals draft class had a total of eight Major Leaguers with Albert Pujols and Coco Crisp leading the charge. Coco Crisp produced a solid 16.9 WAR, but Albert Pujols accumulated an astounding 53.5 WAR in his first seven seasons. The Cardinals had three first round picks in this draft and almost all the value came from a seventh and thirteenth round selection. This goes to show how complicated it is to scout and develop Major League talent.

The 1989 Twins drafted several important contributors to their 1991 championship team in Chuck Knoblauch with 33.6 WAR and Scott Erickson with 18.4 WAR. They also drafted future Rookie of the Year winner, Marty Cordova, in the tenth round and he amassed a total of 5.7 WAR. The Twins drafted four other eventual Major Leaguers led by University of Minnesota Left-Handed Pitcher, Denny Neagle, with 14.8 WAR.

MLB Success Rate by School Type and Position Group

With the margin for a successful draft being so thin, it would be beneficial for an organization to know which type of player has the best chance of cracking the Major League roster. The chart below is broken down by the school type the player was drafted from and their primary position at the time of the draft. The school types are listed as follows: 4Yr represents college, HS represents high school and JC represents a junior college.

College pitchers have the highest success rate with 20% of left-handed pitchers and over 17% of right-handed pitchers making the Major Leagues. This is likely due to the high churn rate of Major League pitchers as well as the perceived Major League readiness of college pitchers. Shortstops also have a relatively high success rate across all school types with every shortshop at or above a 15% chance of making a Major League roster. I believe there are two main reasons for this. The first is that most amateur teams play their best player at shortstop due to the difficulty of the position and the propensity of plays the position is involved in. The second is that shortstops are athletic enough to play many different positions and this versatility allows these players to have more opportunities to eventually crack a Major League roster.

Where to Find Major League Talent?

Organizations are always on the lookout for Major League talent, but where do most of them come from? If a team could identify the country’s hot spots of talent, they could allocate their personnel and travel resources more effectively and efficiently to gain an advantage over other teams. The heatmap below shows where all Major League players that were drafted came from in the contiguous states using their school’s coordinates.

The state of California clearly produces the most Major Leaguers. This is no surprise due to the prestigious baseball colleges in the area as well as the high schools that allow their players to play baseball year-round. The usual suspects are here as well such as Florida and East Texas, but there are a few things that surprise me. The first is the number of Major Leaguers that come out of Southern Kansas and Oklahoma. The University of Oklahoma, Oklahoma State University and Wichita State University have done a good job of producing Major Leaguers over the years. I am also surprised by the dearth of Major Leaguers found in the Mountain West. This is most likely due to the overall sparseness of the population, but it is still surprising to see such a large gap of overall baseball talent in the nation.

Conclusions

There are several conclusions that can be drawn from this study.

Finding Major League talent is not easy. Over 85% of drafted players never make it to the Majors and only 3% of drafted players contribute more than 5 WAR in their team-controlled seasons.
Appreciate home-grown stars because they are few and far between. On average there are only three players selected every year that produce over 25 WAR in their team-controlled seasons.
College pitchers and shortstops have the best chance to reach the Majors at some point in their career.
California is a hotbed of Major League talent.

Data Acknowledgments

All the draft data was obtained from Baseball-Reference.com and all the WAR figures were obtained from FanGraphs.com.

Click here to view code on GitHub.

An Analysis of Minor League Development Paths

For years, Major League Baseball organizations and their fans have focused on their prospects. They wonder who will make it to the Majors, how productive they will be and when they can be expected to contribute at the Major League level. I attempted to answer these questions by looking at drafted players from prior years and examining their level reached by years of experience. Based on historical data, what can we expect from Minor League players going forward? I believe the data below provides useful information that shows league wide player development trends.

Methodology

My population consisted of 8,748 players that were drafted and signed with their team from 2000 to 2009. I chose this period because it was one of the most recent time periods that allowed me to view almost every player’s full amount of team controllable years through the 2019 season. I then split the population into position players and pitchers according to the position listed on Baseball-Reference’s draft data.

Next, I took the level that the position player had the most plate appearances in for each season and assigned this level to the player’s corresponding year in his professional career. I did the same thing for pitchers, but I chose batters faced instead of plate appearances. I repeated this process for the first seven seasons of each player’s professional playing career.

I chose the level with the most plate appearances and batters faced instead of highest level reached because there are times throughout the season where a player may spend some time at an affiliate to fill the roster for a week or two due to an injury in the organization. Once the injured player returns, the promoted player will be sent back down to his original level. For this reason, I believe that spending most of the season at a level is a more accurate depiction of a player’s development level than choosing the highest level reached in a season. I decided to analyze the first seven seasons because that is how long a drafted player must wait until they can reach minor league free agency and the team no longer owns the player’s rights. Below is an example for 2002 draftee Denard Span to help understand the process of my methodology.

Denard Span was drafted by the Minnesota Twins in 2002 so his first professional season takes place in 2002 and his seventh season takes place in 2008. Span did not play any games in 2002 so his level is listed as DNP. DNP in this study signifies any season that a player did not play for an affiliated team in the United States. He then spent the entire 2003 season in Rookie ball. In 2004, he had 19 plate appearances in Rookie ball and 282 in A-ball, so we put an A in the Year 3 column. Span had 212 plate appearances at High-A and 304 plate appearances at the AA level in 2005 and he spent the entire 2006 season in AA as well, so we enter AA in the Year 4 and Year 5 columns. He then spent the entire 2007 season in AAA with 548 plate appearances. In 2008, Span had 184 AAA plate appearances and 411 Major League plate appearances. Therefore, we enter MLB in Year 7.

After finding the development path for each drafted player, I then found the year that each player debuted in the major leagues and calculated their WAR total for their debut season plus another six full years after their debut to simulate the amount of team control WAR. This assumption is not perfect because it does not consider a player’s actual service time and it may underrate players that were optioned back down to the minors for long periods of time. However, I believe this method is a decent facsimile for the value a player brings to an organization in his team-controlled years. Let us return to our Denard Span example. Denard Span debuted in 2008, so we sum his WAR totals from 2008 to 2014 and we find that he produced a total of 22.5 WAR in those seven seasons.

Overall WAR and Chance of Reaching the Majors

I have two goals I hope to accomplish with the tables in this article. The first is to show the average amount of WAR a player generates during his team-controlled years given his level assignment and experience. This information is color coded by quantity and is shown on the left side of each cell. Green represents a high amount of WAR and red represents a low amount of WAR. The second is to show the percentage of players in each cohort that have reached the Major Leagues at some point in their career. This figure is shown on the right side of the cell with a data bar. If a level and year combination did not have at least fifty players, I omitted them from the chart to avoid having small sample sizes misrepresent leaguewide tendencies. To find the average amount of WAR I decided to take the sum of WAR divided by the number of players that have reached the Major Leagues.

As expected, the higher the level and the less experienced a player is, the more WAR and the better chance a player has of reaching the Majors. This makes sense because if a player is performing well at their assigned level, they will be promoted to the Major Leagues quicker than the rest of the sample. The exceptions seem to be in years three and four where the average WAR is higher for players that sat out the season or played in Rookie ball than players who played in Short-season ball. This is most likely due to the small sample of players that were on a rehab assignment that eventually made their way to the Majors. Since I divided by Major Leaguers instead of total players, this allows one or two players to skew the WAR figure when very few players make the Majors in a sample.

This table gives us a good deal of information. However, we can learn more by splitting the population into different groups of draftees and analyzing the different development paths taken by drafted players.

WAR and Chance of Reaching the Majors for College Players vs. High School Players

The first difference I decided to look at was between college and high school draftees. College players are three to four years older than their high school counterparts, so it stands to reason that their development paths should be quite different.

The first thing that jumps out is that high school players take longer to reach the Majors than college players. High schoolers did not have at least 50 players reach MLB until Year 5. Meanwhile, 50 or more college players reached MLB starting in Year 3.

High school players also seem to have a more uniform start to their career than college players. The only playing level in our table for high school players is Rookie ball and the highest level in our year 2 sample is Low-A. Meanwhile, a college player’s career can range anywhere from Rookie ball to A+ in their first professional season and Rookie ball to AA in their second professional season.

I also find it interesting that high school players have a higher average WAR than college players. This could be because many of the best amateur players forgo college altogether to get a head start on their professional careers and this would create a selection bias in our data that skews toward high school players.

WAR and Chance of Reaching the Majors for Position Players vs. Pitchers

The next thing I wanted to investigate was the difference between position players and pitchers. Both groups have quite different jobs and it is possible that they could have radically different development paths.

The main difference between these two tables is the average WAR for position players at the Major League level is much higher than pitchers at the Major League level. This is probably because many drafted pitchers eventually end up in the bullpen where they are unable to accumulate as much WAR as a position player due to their limited playing time.

WAR and Chance of Reaching the Majors by Position and School Type

We have compared the differences between school type and position separately, now it is time to analyze each group of draftees by school type and position together. The four tables listed below are in this order: College Position Players, High School Position Players, College Pitchers and High School Pitchers.We should be able to use these four tables to determine which minor league players tend to have the best chance of making the Majors and how productive they will be if they do make it to the Majors. Teams may also be able to use this data to guide them in assigning players to a level for the upcoming season or even when to release a player who has not lived up to expectations but may have a higher perceived ceiling than his teammates.

Many of our observations from earlier are still true. High school players produce more WAR than their college counterparts, but they take several years longer to reach the Majors and the players that get promoted earlier in their careers produce more WAR.

The last thing I want to make clear is that these figures are all aggregates and they cannot be used to predict an individual players success. Just because a college pitcher makes it to AA in his second season, does not mean that he has a 62.61% of making the Majors or that he is expected to produce 3.7 WAR. It just means that similar players have had that amount of success in aggregate. However, I do believe that it shows realistic expectations for career development of drafted players and that it can be used to help teams make informed decisions about where to place players in their organization and create timelines for realistic windows of contention.

Conclusions

There are several conclusions that can be drawn from this study.

On average, High School amateurs that make the Majors produce more WAR than college players that make the Majors.
Position players produce more WAR than pitchers.
College players reach the Majors faster than high school players.
If a player reaches AAA, it is highly likely they will play in the Majors at some point. Almost every AAA cohort had at least 70% of their population make a Major League appearance.
The less time a player spends in the minors, the more WAR they produce.

Data Acknowledgments

All the minor league playing time data was obtained from Baseball-Reference.com and all the WAR figures were obtained from FanGraphs.com.