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Doctored Balls, Confiscated Hats, and Notable Changes in Spin Rate

MLB might be cracking down on doctored balls. Significant changes in spin rate are one indicator of potential cheating. Let’s check changes in spin for notable Cardinal pitchers.

AP Photo/Charles Rex Arbogast

The war against doctored baseballs appears to be coming. The Cardinals might have witnessed MLB’s first shots when veteran umpire Joe West asked Gio Gallegos to remove his cap before his May 26, 2021 appearance against the White Sox.

Gio’s cap had a circular stain, built up from repeatedly tugging on its bill. The mark could be entirely natural – the result of habitually touching his cap with dirty fingers. It’s also possible that Gallegos had loaded up his brim with illegal spin-assisting, performance-enhancing gunks.

Regardless, West’s crew noticed the stain (or were tipped off) and decided they would take it upon themselves to enforce MLB’s long-overlooked rules on doctoring baseballs. They took Gallegos’ hat away before he even took the mound.

Cardinals’ manager Mike Shildt went off after the game, monologuing not so much at West, but on the prevalence of doctoring baseballs throughout the game. He claimed that if the league wanted to enforce the existing rules, all they had to do was check spin rates and watch the games. What pitchers have seen a massive increase in spin? Who never goes to their mouth with their fingers? The evidence of who is using and who isn’t, he claimed, is right there in front of everyone!

Shildt did acknowledge that Gallegos uses substances like sunscreen, rosin, and dirt to help with grip and combat sunburns. He also claimed no knowledge of any Cardinals’ pitcher who used illegal concoctions to dramatically impact ball movement and pitching performance.

Everyone is doing it. But not the Cardinals, of course.

There has been no announcement from the league about penalties toward Gallegos or Shildt. I checked with Jeff Jones of the Belleville News-Democrat to see if he anticipated any response from MLB officials down the road. He indicated that Gallegos’ hat had gone into the “black hole” of MLB’s efforts at “collecting data” on the baseball doctoring problem.

Jeff’s point is not very subtle. The league knows that pitchers are cheating. Managers know. Hitters know. Pitchers know. The media knows. Fans know. Leaked reports indicate that the problem is widespread. Still, until recently, nothing had been done except the confiscation of some baseballs and a hat.

Recent reports indicate that MLB might be preparing to take more direct action to control the problem.

It begs the question: why now?

There are increasing complaints from some within baseball about the aesthetics of the current game. Part of this is due to natural evolution. Pitchers are stronger and bigger, with better training techniques and access to advanced analytics that enable them to maximize their stuff. Hitters are doing the same, tailoring their swings to generate more power, often at the expense of strikeouts.

Other reasons are less natural. MLB has openly tinkered with the baseball. This spring they announced that they were loosening the internal windings of the ball, which slightly lowered the weight of the baseball without changing its size. Simple physics tells us that less mass at the same force (contact with the bat) should lead to less distance traveled.

More pitchers with video game stuff, more batters with three-true outcome swing styles, and a less productive ball have added up to a game with less offense that the league views as less fun.

Baseball is exploring a variety of ways to improve play. In the Atlantic League, they have moved pitchers back a full foot, placing the mound at 61 feet 6 inches from home, presumably to give hitters just a bit more time to react. Robo umpires are likely coming soon to the majors, which would provide hitters with a more consistent strike zone.

Oh, and the league could begin to enforce rules about the use of foreign substances that have been on the books for decades.

Let me make that point more obvious. The league’s growing concern with doctoring baseballs is not necessarily some altruistic effort to preserve the purity of the game. That’s a secondary byproduct to creating a more enjoyable entertainment experience.

They started small – collecting samples of baseballs to test for illegal substances.

Then they were more direct – confiscating Gallegos’ hat and baseballs used by Dodger’s starter Trevor Bauer.

This past week, the league suspended four minor league pitchers for doctoring balls. MLB hurlers should take that as a shot across the bow. The league is coming for them next.

Immediately MLB reporters began a more careful examination of pitcher performance and spin rate. The aforementioned Bauer, who has essentially admitted to doctoring balls, saw a hefty decrease in spin rate in recent starts. Yankees’ ace, Gerrit Gole, saw a 6% drop in spin rate in a game last week. He allowed five runs in five innings in that game.

(Update: Cole also essentially admitted to doctoring balls in a must-watch press conference last night. See the video in this Tweet.)

When Gio Gallegos switched hats, he also saw a decrease in spin rate. That decline was small – just 30 rpm – and well within the margins of normal variation game-to-game. That change is also consistent with the measured impact of the substances Shildt identified – rosin, dirt, and sunscreen.

Baseball isn’t likely to crack down on the use of sunscreen in a summer sport played outside. They have allowed rosin bags on the mound for decades. The mound is made of dirt; it’s not like baseball can ban that. They also aren’t interested in stopping players from going to their mouths, licking their fingers, or tugging on their caps.

Instead, baseball is doing exactly what Shildt suggested they do: look for the extremes. Find players with significant variation in spin rate data (let’s call that 150-300 rpm) and you’ve probably found your cheaters.

Ok. So, let’s do that. Let’s dig through spin rate data for Cardinals hurlers and see how they’ve changed over the years.

I admit that I start down this path of investigation with some trepidation. Let me make one thing very clear: regardless of what data I find, I can neither implicate nor vindicate any pitcher of doctoring baseballs.

There are so many factors that contribute to pitch performance, spin rate, and results. Health, mechanics, changes in usage and role, coaching, age, repeatability, and sample sizes are just a few of the factors that could cause a change in spin rate over time.

That said, a significant change in spin rate over time is a clear indication that something has changed. And that something is worth investigating.

The methodology here is simple. I’m going to look at the top two pitch types for a sample of Cardinals pitchers – the starters and key relievers – and then evaluate changes in spin rate over time. I’m trying to avoid small samples and injuries, so the years and pitches used for each pitcher vary. Here are the results and we’ll look at each pitcher individually:

Spin Rate Changes over Time, Notable Cardinals Pitchers.
Baseball Savant

Cardinals Pitchers with a Notable (+150 or more) Increase in Spin Rate

Adam Wainwright
Wainwright has experienced a late-career resurgence and much of it can be tied to a curveball that has significantly improved spin and movement when compared to healthy seasons in his mid-30s. Wainwright’s curve spin rate has increased steadily every season since 2017 (I skipped 2018 because of sample size), and now ranks in the top 15% of the league. He has gained 186 rpm over 4 years. His fastball spin has increased as well, with a gain of 75 rpm since his last full season in 2019.

Jack Flaherty
Flaherty’s fastball has tracked pretty closely with the up and down seasons he’s had in his young career. His fastball spin rate is up 55 over last year’s lost season but it’s only a marginal 29 rpm over 2019. His slider, though, has changed dramatically. He showed a 150 rpm improvement between 2018 and 2019, and has added to that since. In 2021, before his injury, he was +175 in slider spin from his first full season.

Gio Gallegos
Gio’s fastball spin has been relatively consistent, floating between a high of 2428 and a low of 2359, a difference of 69 rpm with no trend line. His slider, on the other hand, has shown massive improvement. He had an rpm of 2120 in a tiny sample size in 2018. The next season he saw his first substantive action, improving that to 2242. That has now jumped to 2498, an improvement of 256 rpm. Since Gallego’s hat was submitted to MLB, Gallegos has had four outings. His slider spin rate jumped the next day to 2547 but has been falling on average since: 2470, 2436, and 2430 respectively.

Cardinals Pitchers with Relatively Consistent Spin Rates

Kwang-Hyun Kim
Kim’s spin rates are remarkably consistent. He’s increased 1 rpm over 2020 with his fastball. He’s down 9 rpm on his slider. His pitches are essentially identical to last season.

John Gant
Gant’s sinker was very consistent out of the bullpen – ranging from 2423 to a high of 2466 in 2019. His changeup is equally consistent. Both pitches have dropped in spin rate with a move from the bullpen to the rotation, but the drops aren’t what I would classify as highly significant.

Alex Reyes
Reyes’s crazy path to the majors makes evaluation difficult. We do have spin rate stats from his starts in 2016. His numbers look A LOT different than they do now. But he’s also a completely different kind of pitcher. I’ve decided to throw out everything before 2020. Comparing 2020 to 2021, both his slider and four seam fastball have fallen in rpm but not enough to indicate a significant change.

Cardinals Pitchers with Notable (-100 or more) Declines in Spin Rates

Carlos Martinez
Martinez, like Gant, has transitioned back to the rotation after spending time in the bullpen. He’s also battled injury. From 2017-2019, Martinez was relatively consistent, showing a slight bump in fastball spin by moving from the rotation to the pen. His slider pretty much stayed as it was. Now a starter again, Martinez’s spin rate has dropped pretty heavily, both on his 4-seamer and his slider.

Genesis Cabrera
Cabrera’s overall spin rate has dropped a bit since his debut in 2019. His curveball rate is most notable, falling almost 170 points in two years. An argument can be made that a decline in spin rate could indicate a player has stopped doctoring balls because of MLB’s new efforts. That doesn’t seem to be the case here. The bulk of Cabrera’s decline came from 2019-2020. It seems like he’s actually learned to better control his stuff even if it means less spin.

What Should We Make of this Data?

I know some fans will take the first section and overreact, claiming that the increase in spin rate over time from Wainwright, Flaherty, and Gallegos proves they are cheaters.

The data simply doesn’t support that kind of conclusion.

Take Wainwright. Yes, there are statements from sources in the media that implicate Waino, along with numerous other pitchers, in doctoring baseballs. (See this article from ESPN back in January.) Wainwright, though, contributes his late-career renaissance to improved health. He’s been honest about the pain and discomfort that nearly drove him from the game several years ago. That pain has improved significantly. He’s pitching comfortably now. He’s also throwing his curve with more spin than he did before those injuries set in. That’s a change I can’t account for based on the narrow focus of this research or just with better health. Change has happened. Why? My next step will be following Shildt’s recommendation. I’m going to watch Wainwright pitch, looking to see what he touches with his pitching hand – does he go to his glove, belt, or hat? And what he doesn’t touch – does he go to his mouth?

What about Flaherty’s slider? Yeah, he has a pretty massive increase in slider spin from his rookie season. He was also 22 years old back in 2018. He’s 25 now. Considering Flaherty’s talent level and scouting profile (even as a minor leaguer), that kind of change in pitch performance isn’t completely absurd. Yes, it’s uncommon for a pitcher to show that kind of improvement in spin but that’s also how exceptional prospects develop into actual aces. It does happen and it’s not just because of pine tar.

And Gallegos? He does fit what MLB is looking for: A notable increase in spin rate and noticeable physical evidence of foreign substances. Joe West and crew did what they should have been doing for years and took steps. Now the game has Gallegos’ hat to test and decisions to make. It’s worth reinforcing that so far MLB has not done anything to Gallegos and indications (which I double-checked with knowledgeable sources) are that no action is forthcoming. That might not definitively prove Gio’s innocence, but it certainly doesn’t demonstrate his guilt. Meanwhile, with MLB’s eyes fixed on him, Gallego’s slider spin rate is down a bit since the confrontation but still within spitting range of his season average. Maybe, hopefully, Gallegos has just made himself into an exceptional talent with a dirty hat. This beats watching, though.

What about the rest of the team? The margins of the roster might hold more telling results. You can check spin rates for each player at Just search for a player and look at their Statcast stats for “spin” under the “pitch tracking” section. You can sort by pitch type, spin, and year. You can also watch live game data at Savant to see what pitchers are doing in real-time. Compare that to what you see and what pitchers have done in the past.

Shildt maintains the evidence is there. We’ll just have to see if MLB gets serious about taking any action and if that action will involve any Cardinals. If things change in the coming weeks, as this controversy continues, I’ll keep you informed.