Gerrit Cole and the still-evolving sticky stuff mystery

Just two months ago, fellow PSA writer, Joshua Diemert, gave us an overview of the Yankees rotation spin changes after the sticky stuff ban. The results pointed to Gerrit Cole as a likely user of something potentially as powerful as the infamous Spider Tack. Cole, among others across the league, saw a decrease in his fastball spin of more than 200 RPM after the crackdown.

In his first few starts following the ban, he looked shaky to say the least. This isn’t too surprising. Grip agents are used to have better feel for the ball in your hand. Suddenly removing that agent from play means there is an inevitable adjustment period. It seems as if Cole has adjusted. He’s been very good thus far in August, and the peripherals have pointed to him still being elite. Of course, he has lost movement, but he has seemed to figure out pitching in the post-no sticky stuff era.

But is it actually the post-no stick stuff era? According to Eno Sarris, this may not be the case. In his piece this week (subscription required), he details how some pitchers have experienced sudden spin recoveries in recent weeks, plus how in-game variation in spin is higher than ever right now. After an initial adjustment period, some pitchers appear to have built in some workarounds for the league’s enforcement policies. It’s impossible to say for sure, as all we have is data, but the numbers put forth by pitchers such as Chicago’s Dylan Cease and Lance Lynn are intriguing. Somewhat miraculously, they’ve both experienced a drastic spin recovery.

This brings us to Gerrit Cole. If the Yankees’ ace has developed workarounds of his own, he could risk a suspension during a stretch-run where the Yankees are gunning for the best record in the AL and the division title. It’s a significant risk.

The numbers tell a pretty plain story. We can see which pitchers have boosted their spin recently and have seen their spin fluctuate in-game, suggesting they’re working in sticky stuff when they feel they can get away with it (e.g. in the innings directly following a sticky-stuff check from umpires). Thankfully, that allows us to investigate Cole himself.

Let’s dig in on Cole’s spin. Here is a chart of his spin-to-velocity ratio (SVR) throughout the 2021 season on a game-by-game basis (it’s important to adjust for velocity, as harder pitches naturally come with more spin):

This all looks fairly heartening. Cole’s ratio across all pitches has relatively level since the league’s crackdown two months ago. If Cole had returned to using the sticky agents, we would have expected the two points following August 1st to be significantly higher than those immediately before August. But as Sarris’ sources highlighted, it may make more sense to look at this on an inning-by-inning basis.

Looking at only one game won’t tell us much since. The following chart shows Cole’s fastball SVR from his last four starts, separated by start. As Sarris detailed in his article, the variance on an inning-to-inning basis has increased in August when compared directly to the games following the sticky stuff crackdown. For that reason, I selected Cole’s two games before he went on the COVID-IL and his only two starts in August.

This probably bodes well for Cole. We can say certainly his spin was very steady in those July starts. In August, the story changes a bit. On the 16th, everything looked stable until the last inning. The same thing happened on the 21st but in the opposite direction. Instead of seeing a drastic decrease in SVR in the final inning, there is an increase. In July, the difference between the minimum versus maximum SVR in the two games were 0.6 and 0.7, respectively. In August, they have been 1.7 and 2.0.

All this being said, no concrete argument can be made that Cole has dipped back into to the Spider Tack. The data has definitely fluctuated in his last two starts relative to previous ones, but even in the higher SVR innings, he has not come close to the levels we saw in April and May.

Over time, we will know more. But in this current moment, this is what we have. It’s something to pay attention to down the stretch of the season, as it’s clear that something is going on with spin rates across the game, and it could spur some sort of further action from the league. Let’s just hope things play out well for the Yankees and don’t throw a wrench into this incredible run.