How worried should the Yankees be about Gerrit Cole and foreign substances?

Over the last three days, the Yankees offense has looked revitalized, averaging over seven runs and 13 hits per game in their series win against the Twins. Unfortunately, that is not the narrative that has dominated the headlines in Yankees Universe. Accusations against Gerrit Cole and his alleged ball-doctoring with foreign substances remain on center stage.

Granted, this is not an issue that solely concerns the Yankees ace. We are witnessing another year of the pitcher, with offense at record-low levels — if the season ended today it would have the highest league strikeout rate ever and the lowest batting average since, you guessed it, 1968. And so MLB has identified foreign substances and their performance enhancing effect for pitchers as the biggest league transgression since the Astros and Red Sox sign-stealing scandals and the PED era.

It has long been known that velocity and movement are the core components of a pitch’s success. More and more now, it is understood that movement plays a superior role in making a pitch unhittable. With the introduction and dissemination of pitch tracking technologies, pitchers have a much clearer picture of how spin affects movement, so naturally a pitcher who wanted to increase movement and thus effectiveness of their pitches would try to maximize spin.

There are a handful of avenues to optimize spin — many of them involving biomechanic adjustments — however the route that yields the most immediate and significant results is increasing one’s grip on the baseball. Eno Sarris of The Athletic detailed how pitchers are using sticky substances to increase the spin of their pitches. Trevor Bauer claimed in 2018 that pitchers could boost their spin rates by as much as 300 RPMs in one start just by applying a sticky substance — and then went so far as to conduct a one-game experiment to prove his case (to speak nothing of the suspicious increase in spin rate starting in 2020).

Now Gerrit Cole finds himself at the center of this league-wide discourse, though it is not the first time he has been implicated. Bauer accused Cole of using foreign substances after the former Pirate and Astro arrived in Houston. Ex-Angels visiting clubhouse manager Bubba Harkins named Cole among those to whom Harkins provided grip enhancers. And now, Josh Donaldson singled out Cole and his conspicuous drop in RPMs in a start following the suspension of four minor leaguers for ball doctoring.

Cole did himself no favors with his vague and stumbling response to a direct question from Ken Davidoff if he ever used Spider Tack — a specific brand of grip-enhancer. And the point Donaldson brought up is a valid one, regardless of your opinion of the forum he chose. So that begs the question, how worried should the Yankees be about Gerrit Cole and his performance going forward?

Before we proceed any further, I must qualify that we have zero material evidence that any pitcher — Cole or otherwise — is using performance-enhancing foreign substances on the ball, just strong circumstantial evidence. However, if we accept the premise that the vast majority of pitchers are boosting their spin rates with sticky substances, this has serious implications should the league indeed crack down. So let’s look into Donaldson’s allegations against Cole, ask if there is any truth to his statements, and see how that manifested in Cole’s performances.

The main evidence for Donaldson’s accusations was the aforementioned drop in RPMs, and this makes sense — a stickier grip is the mechanism for spin enhancement, so if Cole all of a sudden stopped using a foreign substance prior to his June 2nd start against the Rays, we’d expect to see the RPMs plummet.

This was indeed the case, as relative to his season averages, the spin rate on his four-seamer dropped 110 RPMs, the curveball 70, and the slider 38. Then in his next start against the Twins, the four-seamer was still 52 RPMs below season average while the slider dropped 80 (the curve was right at his season average).

How are we supposed to interpret this? On the one hand, these are large enough deviations in spin rate to be significant. On the other hand, they are still a long way away from the 200-300 RPMs that Bauer claimed could be added by using a foreign substance.

Since we know that spin generates movement and movement helps with a pitch’s deception making it harder to hit, let’s next investigate the potentially affected pitch metrics. Ominously, he lost about two inches of rise on the fastball and four inches of drop on the curveball against the Rays, and an inch of rise on the fastball and three inches of drop on the curveball against the Twins. He also lost two and three inches of horizontal run on the slider in respective starts.

Losing this movement, one might expect hitters to perform better against Cole in these two starts. The results are mixed. Over those two games, his barrel rate, whiff rate, and xwOBA were all worse than his season averages. However, his strikeout rate hovered right around the season mark while his hard hit rate and chase rate actually improved.

So what’s the verdict? Cole’s loss of spin rate is enough to merit conversation — that said, he showed he was more than capable of dominating a major league lineup with “underperforming” pitches. If Cole was using foreign substances to augment his spin rates, he may have to find a different method to recover those RPMs should the league follow through and enforce the foreign substance rule.

However, as John penned so eloquently yesterday, it’s hard to trust the league to do the right thing given their recent behavior. Especially considering this scandal coincides with a bargaining year, is a perfect opportunity to deflect blame for flailing offenses onto the players in the same season that the league deadened the baseball, and is a chance to introduce a rift in the players when they should be coming together as one. What I can confidently say is that we can feel secure that Cole will continue to pitch like the ace that he is.