The Houston Astros are a league leader in using data analytics to identify and develop talent. Recently, their use of spin rate has become more public and the success they have had finding pitching talent speaks for itself. There is more to the Astros' success than finding players with certain spin rate characteristics, but it is likely the first step they take when evaluating pitchers. With the 2020 season wrapping up, I wanted to look ahead to the free agent pitchers and see if any are good fits when using this method of assessment.
Using Past Astros Acquisitions to Identify an Ideal Pitcher Profile
There are numerous articles and reports to get started building a profile that the Astros prefer. Here are a few articles that discuss the Astros' preferences and how they use those pitch characteristics to be successful:
Highest Team Spin in 2017-2018 - https://www.crawfishboxes.com/2018/5/3/17316840/digging-into-the-data-astros-spin-rates
Ryan Pressly's Transformation - https://www.theringer.com/mlb/2019/6/3/18644512/mvp-machine-how-houston-astros-became-great-scouting
Gerrit Cole's Transformation - https://fivethirtyeight.com/features/how-gerrit-cole-went-from-so-so-to-unhittable/
From this information I identified some characteristics the Astros are using to look for pitching potential:
- Above average four-seam fastball spin
- Above average curveball spin
- High use of a below average two-seam fastball/sinker, especially with poor performance
To validate these characteristics and their utility in identifying pitching talent, I looked at the pitchers on the Astros 2019 ALCS roster that were acquired after 2015 when spin rate data became available. There were seven pitchers who met these criteria, and Joe Smith was removed because he throws from a sidearm slot. Below is a breakdown of the pitchers used for the initial analysis and when they were acquired by the Astros:
Pitchers Traded for:
Justin Verlander - 2017
Gerrit Cole - 2018
Ryan Pressly - 2018
Roberto Osuna - 2018
Zack Greinke - 2019
Pitchers Signed in Free Agency:
Hector Rondon - 2017
To analyze the Astros' preferences for a high spin four-seam fastball I used Statcast data for each player 2 years before joining the Astros, and all available data since. I also used league wide pitch data from 2017 to 2019 to get a league average and standard deviation spin rate (2270 +/- 175 rpm). The figure below shows the results:
The data on four-seam fastball spin rates provides the following insights:
- 4 of the 6 pitchers had spin rates greater than the league average before joining the Astros, and 3 had spin rates more than one standard deviation greater than the league average.
- 5 of the 6 pitchers had spin rates greater than the league average after joining the Astros, and 4 had spin rates more than one standard deviation greater than the league average.
I used the same analysis methods to look at curveball spin rates. To make the analysis a little easier, I combined all pitches tagged as a Knuckle Curveball into this category. The league average values were 2505 +/- 295 rpm. The following figure shows the results:
Hector Rondon and Roberto Osuna don't throw a curveball so their spin rates were zero leaving only 4 pitchers for comparison. The data on curveball spin rates provides the following insights:
- 3 of the 4 pitchers had spin rates greater than the league average before joining the Astros, and 1 had a spin rate more than one standard deviation greater than the league average.
- 3 of the 4 pitchers had spin rates greater than the league average after joining the Astros, and 3 had spin rates more than one standard deviation greater than the league average.
The final characteristic identified in the articles focused on two-seam fastballs/sinkers. This characteristic really has three parts:
- Spin rate. With a two-seam fastball pitchers actually want lower spin to generate more downward movement. The league average values were 2148 +/- 175 rpm.
- Use rate. A pitcher who uses an above average spin two-seam fastball will have more to gain by using it less.
- Poor performance. I used wOBA because it is readily available with Statcast data.
I analyzed two-seam fastball data for each of the six Astros pitchers in those three categories, seen in the figures below.
Justin Verlander doesn't throw a two-seam fastball so there are only 5 pitchers to compare. Looking at the three sets of data together we can see some common trends:
- 3 of the 5 pitchers had two-seam fastball spin rates that were higher than the league average and 2 had spin rates greater than one standard deviation (175 rpm).
- All 5 of the pitchers have decreased their two-seam fastball use, and everyone except Hector Rondon have decreased their use significantly.
- All 5 of the pitchers had high wOBA on two-seam fastballs before joining the Astros indicating the pitch was not effective.
Using the four-seam fastball, curveball, and two-seam fastball data together we can validate the pitcher profile identified in the articles. With the exception of Justin Verlander and Hector Rondon, all of the pitchers were using a two-seam fastball that was ineffective. Spin rates were high, use was high, and wOBA was high for that pitch. After joining the Astros, two-seam fastball use decreased. The Astros instead had those pitchers rely on their high spin four-seam fastball and curveball. Justin Verlander doesn't throw a two-seam fastball but had exceptional spin rates on his four-seam fastball and curveball. Even Zack Greinke, whose spin rates were around league average, decreased use of his least effective pitch. These characteristics helped the Astros identify pitching potential and build their pitching staff.
Identifying Free Agents that Match the Pitcher Profile
Now that the characteristics were validated, I wanted to see if any of the 2020 free agents matched this profile and could benefit from a change in approach. I wanted to find pitchers who met all three criteria. These pitchers will have the most to gain and therefore offer the most value.
There are 47 starters and 53 relievers on the mlb.com list of potential 2020 free agents so I broke them into groups of 10 to keep the graphs readable. I will present them below (as a slide show) using the past two seasons of data for each pitcher and the same methods as above. You can look through each figure yourself or skip to the end and see the pitchers I identified and a closer look at their numbers.
Four-seam fastball spin rate data:
Curveball spin rate data:
Two-seam fastball spin rate:
Two-seam fastball use data:
Two-seam fastball wOBA data:
To filter through all 100 pitchers, I tried various filter combinations that gave me a short list of pitchers. Ultimately I landed on parameters that required a pitcher to have either an elite four-seam fastball or curveball and two-seam fastball characteristics that indicate decreased use would benefit them. The parameters used were:
- Four-seam fastball spin in the 75th percentile or better (> 2388 rpm) OR
Curveball spin in the 75th percentile or better (> 2704 rpm)
- Two-seam fastball spin greater than the league average (> 2148 rpm)
- Two-seam fastball use greater than 10%
- Two-seam fastball wOBA greater 0.300
This cut the list down to 10:
This group's four-seam fastball data:
Adam Wainwright and Trevor Cahill's four-seam fastball spin is below the league average which could be problematic for this profile. I will eliminate them from further analysis.
All of the other pitchers have good spin on their four-seam fastballs which meets the ideal pitcher profile. Yu Darvish, Rick Porcello, and Tommy Hunter have especially good four-seam fastball spin.
Curveball spin data:
Steve Cishek and Arodys Vizcaino don't throw a curveball. They don't exactly fit the Astros profile I've identified and will be eliminated from further analysis. Further analysis into their other pitches could still make them attractive to a similar process, but that is outside the scope of this post.
Rick Porcello and Tommy Hunter have good four-seam fastball spin and also have good curveball spin. Jake Arrieta also has curveball spin that is well above the league average.
Two-seam fastball spin data:
Everyone's two-seam fastball spin is high because of the filter I used, so this metric doesn't provide a ton of insight into potential gains. However, Rick Porcello, and Tommy Hunter have especially poor spin on their two-seam fastballs. Combining this information with two-seam fastball use and wOBA will be more insightful.
Two-seam fastball use data:
Yu Darvish uses his two-seam fastball the least out of this group and therefore might have the least to gain from a decrease in throwing his two-seam fastball. Jake Arrieta used his two-seam fastball more than 50% of the time and would require to greatest change in approach.
Two-seam fastball wOBA:
wOBA on two-seam fastballs were all poor - again because of my filtering process - but Edinson Volquez has especially poor performance. Everyone in the group had a higher wOBA on two-seam fastball than overall. Eliminating two-seam fastball use for a more effective pitch or pitches would benefit their performance.
Based on this assessment I've ranked the top 5 'Astros Type' free agent pitchers for 2020. Each pitcher has above average spin on four-seam fastballs and curveballs and would benefit greatly from decreasing use of a poor two-seam fastball.
1 - Rick Porcello
2 - Tommy Hunter
3 - Edinson Volquez
4 - Yu Darvish
5 - Jake Arrieta
The ability to teach higher or lower spin rates would give a team a huge edge in player development and identifying high value players who could improve their spin rates on certain pitches. Gerrit Cole saw increased spin rate on his four-seam fastball after joining the Astros. He attributes this to adjustments in grip and release but the spike has caused controversy around the league. Spin is currently considered a trait that isn't alterable, but more research with high speed cameras like Edgertronic or Rapsoto could crack the code to perfecting a pitch's spin rate.
Identifying these characteristics is far from all the Astros do. Pitchers have to commit to changing their pitch selection. Additionally, locating a fastball up in the zone, like the Astros prefer, requires solid command and confidence from a pitcher. Maybe the Astros or another team will sign one of these pitchers this offseason and convince them to change their pitching style. I think it would benefit their career and in turn the team who signs them.
More analysis could be done on this group of pitchers. Steve Cishek and Arodys Vizcaino might have great spin on their sliders and adding slider spin could reveal other potential pitchers. Additionally, the Cubs have implemented an approach that is exactly the opposite, focusing on pitchers with especially low spin two-seam fastballs and changeups which leads to better movement in the bottom of the zone. A club could optimize each pitcher based on their spin profiles and find great value in the free agent market.
Who do you think I missed as a high spin pitching target this offseason?