MLB Announces a Crackdown on Foreign Substances

One of the bigger on-field stories of the 2021 season has been which pitchers are using foreign substances, and how much help they’re getting from it. Whether it’s Giovanny Gallegos and hat-gate, Gerrit Cole’s word salad about Spider Tack, or Trevor Bauer’s wildly fluctuating spin rate, what pitchers do to the ball has been a hot topic. Yesterday, the league opened a new chapter in the saga when they released a memo that details a drastically increased enforcement policy, one that promises more suspensions than seemed imaginable only a year ago.

The new rule is draconian and more or less without exception. If a pitcher is caught with foreign substances on the ball or on their person, they’ll be immediately ejected from the game. They’ll also be automatically suspended. The memo, which FanGraphs obtained a copy of, doesn’t specify a suspension length. It does tie the suspensions to the existing rules and past precedent, however, which suggests a 10-game suspension with pay for any violations, a figure the league made explicit in its press release.

“Any foreign substance” is a massive change from the way baseball is currently played. The rule is intended, at least in theory, to crack down on synthetic grip enhancers, such as Spider Tack, that create huge increases in grip strength and spin rate. Pitchers have used lower-potency grip enhancers for years; mixing sunscreen and rosin or dabbing pine tar on the fingertips are both time-tested practices.

In disallowing those practices, the league is making things easier for the umpires who will enforce the new crackdown. It’s not hard to imagine what would happen if some but not all substances were banned: a pitcher caught using a prohibited substance would claim it was instead an allowed substance. It’s not necessarily easy to distinguish Spider Tack, a viscous brown substance, from any number of other viscous brown substances. What’s a legal smudge, and what’s an illicit good? Asking umpires to make that decision every time they find anything suspicious would no doubt lead to plenty of incorrect decisions in both directions — legal substances deemed cheating and illegal substances allowed.

That doesn’t make it any easier for pitchers who have relied on relatively benign mixtures of grip-enhancing substances for years, often with the direct encouragement of their team. Tyler Glasnow blamed the partial UCL tear he recently suffered on his need to switch from sunscreen and rosin, a mixture that’s been in baseball longer than Rob Manfred has been alive, to nothing at all, in compliance with new guidance. That’s an impossible claim to verify, but the same muscles that protect the UCL are used in gripping, so it’s not completely outlandish.

Given the near-continual change in the composition of the baseball, which has at times produced rashes of blister issues across the league as pitchers attempt to grip an ever-changing surface, forcing every pitcher who used any substance at all — when Eno Sarris interviewed current and former players about the practice, the practice was considered nearly universal — to overhaul the way they pitch mid-year seems overly harsh, particularly given the league’s previous inaction. In cracking down on extreme offenders, the league might be asking for a rash of grip-related injuries.

One other concern: there’s long been a gentleman’s agreement between pitchers and hitters that low-grade grip enhancers are acceptable as a way of avoiding hit batters on poorly-gripped pitches. That arrangement wasn’t working anymore — again, some of the substances currently in use pass far beyond “grip improvement” and instead are expressly for the purpose of increasing spin — but that doesn’t mean the concern it addressed isn’t valid.

The league paid lip service to this argument in its memo, but I find their argument unconvincing. “…foreign substance use appears to be contributing to an overall decline in control because it enables a style of pitching in which pitchers sacrifice control in favor of spin and velocity,” the memo states. “The number of batters hit by pitches actually has increased as the use of foreign substances has become more prevalent… We are confident that pitchers will be able to adopt a delivery that enables them to grip and control the baseball effectively without the use of an illegal substance.”

But correlational arguments like this are nonsensical. Pitchers are hitting more batters than they used to, and strong grip-enhancing substances are increasingly prevalent, but correlation does not imply causation. There were fewer worldwide murders when dinosaurs walked the earth, but no one is suggesting bringing back stegosauruses to make the world a safer place. Claiming that grip-enhancing substances lead to more hit batters isn’t nearly that poor of an argument, and it doesn’t mean sticky stuff is reducing the number of hit batsman, but correlational arguments are weak by their very nature, even if they don’t involve dinosaurs.

In fact, the argument about what is causing an increase in hit batters is ongoing. Rob Arthur and Russell Eassom found that hitters are responsible for the rise in HBP’s through 2019. Rob Mains looked into whether rivalries affect HBP rates. And Tom Verducci and Ken Rosenthal point towards the increasing prioritization of stuff over command that comes with increased reliance on relievers.

So why is the league “confident” that pitchers will be able to adopt new deliveries mid-season, presumably without hiccups that would lead to a huge spike in hit batters? Per their memo, they talked to “numerous… accomplished current and former pitchers” and asked whether they would be able to pitch with rosin alone. That’s not enough reason to be confident in my book, particularly given that a large number of pitchers have used some amount of grip-enhancing foreign substances for decades.

That’s not to say that pitchers can’t grip the ball without illicit foreign substances. In the KBO, foreign substance use is less prevalent, yet pitchers still manage to control the ball. Umpires there are also allowed to conduct extensive pregame checks, though in practice they rarely do. Two major differences, however, make this a poor comparison. First, the KBO uses powder rosin rather than rock rosin, which functions as more of a drying agent. Second, KBO baseballs are specifically made tacky to enhance grip. MLB hasn’t been able to achieve the same effect, though they’ve tested tacky baseballs in the Atlantic League. Given that they haven’t been able to control the aerodynamics of the existing ball, however, a sudden change for the better in the major league ball seems unlikely.

And the timing of this increased enforcement doesn’t allow much time for experimentation. Perhaps most pitchers will eventually be able to find a combination of a new grip and application of the allowed rosin bag that gives them confidence in their grip while eliminating the spin-enhancing properties the league is targeting. Can they do it in seven days in the middle of the season? I’m not sure of the answer, and I doubt that pitchers are either. Those who have always used some mild form of grip enhancement will likely be starting more or less from square one.

Had this rule been announced after the end of last season, pitchers could have experimented with it in the offseason. Had the league provided some legal way of gripping the ball beyond the existing rosin bag, which many players have found insufficient for ages, the hue and cry from pitchers across the league would no doubt be less deafening. Glasnow specifically mentioned the need to change grips mid-season as a concern, and letting players figure this out in low-intensity offseason settings seems prudent for a move the league claims will increase player safety.

What’s more, implementing a new policy without first testing it means that we don’t know how effective umpires will be in policing substances. The league hasn’t publicized exactly how umpires will conduct foreign substance searches. Their memo said only that “The umpire will have the discretion to inspect the ball, as well as the pitcher’s hands, uniform, hat, glove, etc.” They did state that inspections will generally be conducted between innings, which might give enterprising players a way to get sticky early in the inning and lose it before inspection. The league might yet catch clever offenders. Starters will be checked more than once during a game, and relievers will be mandatorily checked after the end of their first inning or when they exit the game, whichever comes first. The penalty — 10 games with no replacement roster spot — is steep, which might encourage teams to self-police, as might the memo’s promise of consequences for club officials who supply substances or fail to properly deter their use. But making such a drastic in-season change — without working with the union to understand how players might react — adds to the volatility and uncertainty.

Overall, I think that this policy decision is typical of MLB in recent years: it’s heavy-handed and under-tested, and it goes to great and potentially damaging lengths to address a middling problem. If you had asked me to compile a list of the five greatest issues facing the major league game before this season, I wouldn’t have listed spin-enhancing foreign substances. Bradford William Davis of Insider did just that when rumors of an enforcement step-up first emerged, and while mine might differ in its specifics, I don’t even think excessive foreign substance use would top a list of on-field concerns. It might help tilt the balance between pitching and offense — as Devan Fink recently noted, the effect of high-spin four-seamers on run values is real — but it’s a strange time to address that after such a lengthy period of inaction on the league’s part. A pitcher would be forgiven for thinking this just wasn’t a priority because for a long time (and several seeming experiments from Trevor Bauer), it wasn’t.

That’s all academic at this point, because MLB has made the decision to step up enforcement. Starting on June 21, the new regime will be in effect. Players will likely get caught — perhaps not with the “paraffin, licorice, sand-paper, emery-paper…” specified in the official rules, but with some substance nonetheless. Some pitchers will adapt. Some will have trouble figuring it out. Offense will likely benefit if the crackdown is effective at reducing spin rates. The only thing that’s certain is that there will be a host of major leaguers figuring out how to play a substantially different game in real time.

Update: An earlier version of this article mischaracterized the frequency of checks for foreign substances in KBO games.

Ben is a writer at FanGraphs. He can be found on Twitter @_Ben_Clemens.

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Article idea, perhaps more for rotographs: Pitchers most likely to be affected by lost spin. Either because they’re reliant on high-spin pitches in particular, or because they’ve seen a significant change in spin rate in the last couple of seasons.

Also, I’d like to see someone get suspended for illicit possession of licorice.


Let’s get someone on the sugar content of Twizzlers vs. Red Vines and infer how much stickiness each might provide.