Image courtesy of © Brad Rempel-USA TODAY Sports
This past March, the Chanhassen High School baseball program visited Starters Sports Training in Shakopee to put all of our arms under the Rapsodo microscope. One of the first things we got the data back from Starters was convert all fastballs into Bauer Units.
For those unfamiliar, Driveline Baseball champions Bauer Units as a good measuring stick to tell if a player’s fastball is better suited for a 4-seam or 2-seam based on the spin rate divided by the velocity. If the fastball had a high Bauer Unit — 27 BUs or higher — a pitcher’s fastball would play better with a 4-seam grip. A lower Bauer Unit — says 21 or lower — and it would be better to use a 2-seam fastball. This would give us a fastball roadmap for each pitcher.
Why is knowing fastball spin rate important? After all, for generations players and coaches used their eyes and intuition to figure out how a fastball moves. It’s heavy. It has late-life. It has rise. It has sink. Why should we strive to assign a number to every aspect of the game?
As a real world example (and to loosely tie this into a Twins-related subject for Twins-related website) let’s consider Jake Odorizzi and Trevor May. In terms of velocity, Odorizzi (whose 4-seamer comes in at 92.8 mph on average) has a fastball that is 2 clicks below May’s (94.9). Factoring in spin rate, May has approximately 100 more rpms on his fastball (2,338 rpm) than Odorizzi (2,239 rpm). Based on those two data points alone one might think May has a superior fastball. However, both share fastball Bauer Units of 24. While that amounts to a decisively average Bauer Unit among all MLB pitchers according to the Baseball Savant database, it is partly the reason why Odorizzi can be so effective at the top of the zone with a little less firepower than May.
On the surface, Odorizzi might be considered a softer throwing arm in the modern era — seeing that his fastball “only” averages 93 — but it is with the additional metadata that you can concoct a game plan for him.
Prior to the prolIferation of TrackMan, Rapsodo, et al, pitchers like Odorizzi may have been told to work on keeping his fastball down in the zone — which is exactly what happened to Odor: In fact, both Milwaukee and Kansas City informed Odorizziduring his player development days that if he didn’t adjust and hit the bottom of the zone, he wouldn’t make it in the big leagues. That changed when he arrived in the forward-thinking Tampa Bay organization and he would embrace the high ride heater. This year, 57 of his 70 strikeouts on fastballs have been located in the upper third of the zone or higher. It makes you wonder how many pitchers were jettisoned because they were higher-spin pitchers instructed to throw the ball down in the zone (or else).
How can this information be applied to the amateur ranks?
With regard to the Chanhassen program, we found that the bulk of the fastballs fell within the average Bauer Units range — leaning toward neither end of the spectrum. As a practice, those with average-ish Bauer Units who had three-quarter deliveries were asked to try 2-seam or cut fastballs and those with higher Bauer Units and more over-the-top deliveries worked on getting behind their 4-seamers in efforts to get better spin direction and carry (like Odorizzi).
The high spin Bauer Unit rate guys were interesting to observe. In subsequent bullpen sessions or warmups, some confessed that they were taught to shoot for the knees, a counterproductive concept based on their stuff. It seemed clear that years of being told to hit the bottom of the zone was deeply ingrained whereas intentionally elevating felt foreign. Meanwhile, in game action, you could watch the same pitchers throw fastballs above the belt and hitters swing underneath as they struggled to reconcile the fact that the pitch’s trajectory was not falling the way their brains were suggesting it would.
With high spin fastballs being all the rage and 2-seamers the cargo shorts of the pitching world, we needed to consider what to do with two intriguing outliers with super low Bauer Units.
The first, Cade Plath (2019), was a genuine athlete. Here was a big, strong young man who is headed to play Division 1 football and had a mid-80s fastball. However, the combination of a low three-quarter slot and 4-seam grip seemed to result in a ton of glove-side carry. He also had a Bauer Unit of 15, a telltale sign that a 4-seam fastball might not be conducive to success for him. Following the Rapsodo session, Cade tried out a fresh new 2-seam grip, trying to capture that laminar flowgoodness. In his first live AB session, teammates who stepped into the box against him were impressed by what they perceived as late movement darting to his arm side.
We lacked the funds for a high-speed slow-mo camera but even from the grainy iPhone camera you can still see the difference in movement between the 4-seam grip (from March on the left) and the 2-seam grip (from June on the right):
What was interesting is that those two pitches above — despite having very different movement — spit out virtually the same movement data from the Rapsodo.
This was confounding. We figured he had made the necessary grip change and the feedback from hitters and catchers suggested this pitch was doing something different. Why wasn’t the data saying so? Turns out, Driveline Baseball already studied this very phenomenon. According to their research Rapsodo “detects the ball’s spin rate, spin direction, and velocity and recalculates trajectory based on a physics model – hence why it thinks both pitches shown in the video have nearly identical movement when in reality they are quite different.” In short, there is an issue when using Rapsodo data to try to incorporate a laminar express-type 2-seamer into your repertoire.
Armed with his 2-seam action, Cade’s in-season results were impressive. His walk rate dropped significantly from the previous season and he increased his swing-and-miss rate. A lot of his success came because of his steadfast conditioning, overall athleticism, and the fact he threw a “heavy ball” from a three-quarter slot but swapping out fastball grips played a role in his being able to locate that pitch more effectively.
The other super low Bauer Units pitcher was junior Kody Dalen (2020). During the initial March session, Kody told us that he threw a 2-seamer, even showing us his grip, yet the Rapsodo data didn’t reflect 2-seam action. If anything, it had the exact opposite movement — it had cut and a healthy amount of vertical drop.
The low spin rate made it difficult to hit — another example of the proverbial “heavy fastball”. In season, Kody’s fastballs averaged approximately 80 mph, but touched 84. His 63 percent ground ball rate was second on the staff only to Cade (65 percent ground ball rate) while allowing just seven hits in 18.2 innings. After one of his outings, an umpire, supposedly impartial referees maintaining law and order, approached a member of our coaching staff and said how impressed he was at his movement.
The cases of Cade and Kody raised more questions: Why, if two pitchers who have the same low spin rate, similar arm slots, and used the same 2-seam grip, are they producing two very different movements?
It was only later that we came to find out the difference was generated by how the ball came out of their hand — something that Rapsodo can’t pick up (or the human eye for that matter). In the clip below, you will see a side-by-side of Kody (left) vs Cade’s (right) 2-seam fastball.
For Kody, his 2-seam is punctuated by glove-side run and a late sharp downward break. Cade’s more conventional laminar 2-seamer fights against the glove-side run and moves back toward right-handed batters late in the path.
Now watch how the ball comes out of their hands:
If thrown the conventional way, the two black dots should be spinning outward. Cade, on the right, has his fingers stay behind the baseball at release, imparting both the tilt and spin angle necessarily to give the pitch the standard 2-seam run. Meanwhile Kody supinates his hand at release, getting his fingers to the side of the baseball producing the cut action. This action likely costs him some velocity but the added movement appears to make up for it threefold.
You often hear of pitchers having natural cut on their pitches and this is one of those in action. Kody’s movement is just that.
To revisit the initial question — why is knowing a fastball’s spin rate important — it is because that knowledge helps take the guesswork out. If you know that a pitcher has a high-speed, high-carry fastball, you can work with them to develop a more vertical breaking ball. Now you have a solid plan of attack: high fastballs up at the top of the zone and a 12-6 curveball to drop out of that same tunnel. If you have a repertoire like Kody who has a bunch of pitches that run in to a left-handed batter, it was suggested by one of Starters’ instructors to tinker with a slider to give him a variety of pitches that run in (the Dalin Betances model).
You absolutely could accomplish the same thing without the use of technology but, to paraphrase the reigning College World Series champions’ director of player development, if you don’t use it, you are behind.