A Pitch Design Process to Build an Arsenal
- Cameron Richman
- Jan 9, 2020
- 7 min read
Updated: Jan 29, 2020
By Cameron Richman (@CamRichman)
To preface this, the most important thing to take away from pitch design (and player development in general) is that there is no one way to do something or reach a desired goal. This process is a combination of techniques, tools, and ideas from a lot of different people/places. The goal of this blog is to give coaches and players a concrete process to get started designing pitches. I hope this helps get people on the right track and provides a starting place to use tech to design a repertoire of pitches.
Step 1: Information Collection
Collect a good amount of data first and foremost. This is going to take some time, and obviously you don't have to/want to collect all the data at once. Fastball velocity and spin rate can vary slightly from bullpen to bullpen, so it is important to get enough pitches recorded to get an accurate gauge on what his fastball is doing. The same goes for breaking balls and off-speed pitches, but getting fastball data is going to be the most important. My general guideline is around 100 fastballs and 50 off-speed/breaking balls.
Step 2: Bauer Unit Comparison
Once you get the data collected that you need, you can start to compare the pitcher’s fastball Bauer Units to Major League pitchers.
Bauer Units = Spin Rate (RPM) / Velocity (MPH)
MLB Avg. Bauer Units is around 24
> 25.5 = High Spin < 22.5 = Low Spin
To compare the Bauer Units, here is an awesome resource to do that.
For this example, I am going to use a RHP with an average fastball velo of 87.3 mph and an average spin rate of 2049 rpm. If we enter that into the website, it generates 10 pitchers with the closest Bauer Units to the pitcher you are comparing. Below is what the website generated when I put in the info of my pitcher.
(Cargocultsabermetrics.shinyapps.io)
Step 3: Choosing a Comparable Pitcher
So, we can see that the Bauer Units is pretty average at 23.5, and the comparison tool gave us pitchers with those Bauer Units. The next step is to identify similarities between the big-league pitchers and the one you are comparing them to. This will be a blend of the horizontal and vertical break, spin efficiency, and spin direction. I normally try to start with their horizontal and vertical break and then go from there. In this case, the pitcher I am using has a horizontal break of -12.9 inches and a vertical break of 13.9 inches, on average, and a spin efficiency of 95.1%. Out this set of 10 pitchers, Jon Duplantier in the pitcher that has the most in common with my pitcher. His horizontal break is -11.65, his vertical break is 12.15, and his spin effenciency is 95.3%. Once you have chosen a pitcher you think is comparable, you will have to check their spin axis to see if it is also similar because it does us no good if the spin axis is drastically different in the two pitchers. This website does not have the spin axis data so we will have to do some more digging.
Step 4: Finding Spin Axis
To figure out the spin axis we will use Brooks Baseball. Brooks Baseball is a tremendous source of data that we will use a couple times, at least, throughout this process. Here’s the link below
Once you get on the homepage, just type in the player’s name you are looking for and select their “Pitching Card”. From there, Brooks gives an overview of their repertoire and how it compares to other RHPs in the Major Leagues.
Next, we will select “Scatter Charts” from the top menu as shown below.
(BrooksBaseball.net)
Then, select “Spin Axis” as the Y-axis variable, and change the Time per Point to “Year”. After that, de-select all other pitches except the one you want to look at, in this case the four-seam fastball. The average spin axis (degrees) will show up for all years, but will look only at 2019. The setting I used is shown in the photo below. You can see that the average spin axis for Jon Duplantier in 2019 was 206.07 degrees.
(BrooksBaseball.net)
Step 5: Converting Spin Axis into Tilt
If you are familiar with Rapsodo reports, they display spin direction using numbers on a clock, whereas Trackman tracks it using degrees. It is hard to conceptualize this difference, so we will translate it back into the clock version of spin direction. Driveline Baseball put out a useful article that gives a simple formula to convert the two numbers. I will give an example to go through this equation, and you can follow along with the picture below from the Driveline article.
(Driveline Baseball, Mastering the Axis of Rotation: A Thorough Review of Spin Axis in Three Dimensions, Dan Aucoin)
Jon Duplantier Spin Direction in 2019 = 206.07
206.07 / 30 = 6.869
6.869 – 6 = 0.869
Round down to 0, which in “clock” terms is 12:00
0.869 * 60 = 52.14
Tilt = 12:52
Now that we have Duplantier’s spin direction we can compare it to our pitcher to see if it is close. The pitcher I am using has a spin direction of 1:22 on his fastball. This isn’t a perfect fit, but close enough to get useful info out of it. Using DrivelineEDGE I can compare the two spin directions of the fastballs to get a good gauge of the difference between the two. The video below shows the difference in spin direction with Duplantier on the left and the pitcher I am comparing on the right.
(Courtesy of Driveline Baseball, DrivelineEDGE)
Step 6: Analyzing Pitch and Movement Profiles of Each Pitcher
The next step is to gain insight into what pitches and movement profiles Duplantier has in his arsenal and compare them to my pitcher. We can do this on the same site we compared Bauer Units.
Select player you are interested in from the drop-down menu on the left and then press “Generate Movement Plot”, and the movement profiles graph and movement table will show up on the right.
I show what it would look like in the picture below.
(Cargocultsabermetrics.shinyapps.io)
My general thoughts on Duplantier’s movement plot is that his curveball pairs well with his fastball, his changeup kills enough vertical break from his fastball to be effective, and his slider works as a good accent pitch to the other three. I am fortunate because the pitcher I am comparing and Duplantier throw the same pitches.
Below is a graph showing how their movement plots compare.
(Cargocultsabermetrics.shinyapps.io)
Immediately, there are some things that I can see that can be changed:
1. His change-up doesn’t kill enough vertical break making it too similar to his fastball
2. His slider classifies more as a cutter because of the positive vertical break on the pitch
These will be the two changes we will focus on throughout the example.
*As a side note, it is important to mention, if you get your movement metrics from Brooks Baseball they report movement metrics in Pitch Fx form. This is different than numbers we are familiar with while using Rapsodo because it measures movement from 40ft away, and not from release like Rapsodo does. To convert the movement numbers, multiply pfx_x by -1.8 and pfx_z by 1.8.
Step 7: Making Changes to Match Big Leaguer’s Pitch Profiles
1. Killing Vertical Break on a Change-Up
There are two way we can go about killing vertical break on a change-up. One is killing the spin rate or spin efficiency, but this is a more difficult task because it may involve tweaking the grip of the pitch. The most effective way I have seen is to change the spin direction to get more on the side of the baseball. This way is easier for guys because the grip and feel stays the same, and you just have to play around with wrist tilt.
(Courtesy of Major League Baseball and Michael Augustine)
You can see in the video that Castillo shifts the axis of his change-up with his wrist to kill vertical break and increase horizontal break by being on the side of the ball.
2. Making Cutter into Slider
The main cause for the slider acting more like a cutter is because the pitcher is pushing through the bottom of the ball vs. pulling down on the side of it. This creates a spin axis that is not conducive to getting the desired movement, and also can cause the pitcher to get too much transverse (backspin) instead of more gyro (bullet) spin.
The below video shows how my player’s (on the left) is losing the desired axis and spin efficiency by pushing through the bottom instead of pulling down of the side like Duplantier does (on the right).
(Courtesy of Driveline Baseball, DrivelineEDGE)
These are just two examples of common problems and fixes that I have seen. For the purpose of this post I didn’t go into great detail on some other solutions to these problems and mostly want to focus on the process and tools that go into designing pitches.
Step 8: Analyzing How Designed Arsenal can be Successful
After you design the pitch to your satisfaction, the final step of the process is using Brooks Baseball to find effective ways to utilize the new repertoire of pitches. Go back to Brooks and type in the player you are comparing your guy to. Press “Tabular Data” to get useful information to start utilizing the new pitches you’ve designed.
(BrooksBaseball.net)
From here you can start looking at whatever you feel is the most important for your player, there is no one right way to do this. This tool will make it easier to find ways to effectively utilize the new pitches and find successful throwing them. Some general things I like to look for is how often they throw a given pitch (Pitch Usage), their whiff/swing ratio (Sabermetric Outcomes), and groundball/fly ball percentages (Pitch Outcomes). When I look at these numbers and stats, I like to use the “Z Score” in the “Comparison Mode” menu. This tells me how many standard deviations above or below MLB average is so I can get a good gauge for how effective or ineffective a given metric is.
The menu options I mentioned above in parenthesis can be found on the left side of the webpage as seen below.
(BrooksBaseball.net)
Thank you for reading and following along as I go through this process. I hope it helps you and your pitchers as they continue throughout their careers. Like I said before this is not the only way to go about designing pitches, but this is one that I found is helpful if you want to design pitches that are similar to the best pitchers in the game. If you have any questions on anything or any step throughout the process, don’t hesitate to reach out.
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