The Z Files: Spin City

Be it BABIP, average exit velocity, pitcher velocity or spin rate, it's all about the component contributions. For example, take spin rate. High spin on a four-seam fastball is desirable, while low spin on a splitter is better. Say a pitcher throws each exactly half of the time. His spin rate would be the average. By means of example, throwing a 2500 rpm four-seamer and a 1500 rpm splitter would yield a 2000 rpm spin rate for this hurler. If someone else threw a 2400 rpm four-seamers and a 1500 rpm splitter, but used his fastball 60 percent of the time, his average spin rate would be 2040. Sorting by spin rate would rank the second pitcher higher, even though the first guy's spin on the pitch needing it was higher.

With MLB reportedly about to crack down on the abuse of Spider Tack and other such substances, discussion of spin rate has become all the rage. However, not everyone is breaking it down by pitch. What follows is a look at the 30 highest spin rates this season for a variety of pitches which are more effective with more rpms. The offerings include the four-seam fastball, curve, slider and cutter. Keep in mind backspin helps the four-seamer counter sinking action from gravity, while the latter three pitchers feature horizontal movement, along with vertical drop from gravity. Sinkers, two-seamers, changeups and splitters rely less on spin so they aren't included.

The spin rate and velocity of 2021's top 30 for each pitch is presented, along with the same data from 2018-2020. In order to be included, a minimum of 200 four-seamers is needed while the others used a cutoff of at least 150 pitches.

The intent isn't to provide a warning list but rather a watch list. It's too early to gauge the repercussions if the ensuing pitchers cut back on their sticky substance of choice.

Four-Seam Fastball

Observations

• Four Dodgers made the list
• Jordan Sheffield?!?!?
• Gerrit Cole had a big jump from 2018 to 2019, then stayed the same
• Chris Stratton?!?!?
• Max Scherzer, Yu Darvish and Sonny Gray haven't gained spin, but that doesn't mean they aren't doing something. Still, there's less concern than with Bauer and Kershaw and their year-to-year increase.
• Looking at some of the names on this list, high spin doesn't always equate to effectiveness, but it's good to know in hopes the guy learns how to take advantage.

Curveball

Observations

• Same four Dodgers appear here. This isn't an indictment, just an observation. They are all very good pitchers with outstanding pedigree.
• Adam Wainwright has improved mph and rpm in each year of the study. Maybe it's health, but it seems odd for this to occur at his age.
• Looking at someone like Charlie Morton, keep in mind this is with just over two month of play. Spin and velo may drop organically as the season progresses, and the 2018 and 2019 numbers have that baked in.
• Too bad Jordan Lyles' effectiveness doesn't mirror his spin jump.
• Madison Bumgarner being on both lists is curious, though it hasn't helped him much.

Slider

Observations

• Dylan Cease also made the four-seam list. Don't panic, it could simply be normal development, but it bears watching.
• More relievers are on the slider list that the first two.
• Joe Musgrove also appears on the curve list with his number trending upwards on both.
• Dylan Bundy's slider numbers are on the rise.
• Mentioning Kershaw again implies guilt and I'm trying to avoid that. However, showing increasing trends on multiple pitches could have a common denominator other than organic improvement.

Cutter

Observations

• Darvish shows up on multiple lists, twice exhibiting increasing patterns.
• More instances of Wainwright and Bumgarner. Putting aside the effectiveness aspect, the "veteran getting away with whatever he can" narrative is there for the conspiracy theorists.
• Several relievers show up on the cutter list too.

Final Thoughts

There are certainly ample trends to raise an eyebrow at, encompassing players, teams and types of players. Even so, I'm using this to monitor the pitchers I have rostered as opposed to assembling a list of arms I'm immediately looking to jettison. Keep in mind the seams on the 2021 ball are slightly raised, so some of the spin rate increase this season could be attributable to that.

Part of the problem is a confluence of several factors, so it will be difficult, if it's even possible at all, to isolate any effect of pitchers backing off on gaining extra grip. The weather is warming, we're still not sure how the ball is playing and injuries are influencing the quality of play. Not to mention, there is a chance hitters are beginning to tweak their all-or-nothing approach and favor contact over swinging for the fences.

Just when you think you know the answer, MLB changes the question.