The Pitchers Whose Spin Rates Fell Most After a Crackdown on Sticky Substances

Baseballs aren’t spinning the way they used to.

More than a month into the era of increased scrutiny on the application of prohibited sticky substances to major league baseballs, spin rates on fastballs have fallen about 4 percent, as strikeouts have decreased and on-base percentage has risen — midseason changes without parallel in decades.

The steep drop began around June 3, when the league made it known that it would address the issue directly, and it began to level off around June 15, the date the league announced its enhanced enforcement procedures would begin the following week, including in-game inspections by umpires and the threat of 10-game suspensions for pitchers found violating the rules.

An increase in spin rate can add more movement to breaking pitches. And with fastballs, it allows the pitch to stay elevated longer, making it seem as if the ball is rising.

Although applying any foreign substance to a baseball has been prohibited since the 1920s, the use of sticky substances like Spider Tack ⁠— a powerful adhesive created to help competitive strongmen and strongwomen hoist enormous Atlas stones ⁠— was an open secret, in line with the sport’s tradition of winking at scofflaws until the situation gets out of control.

And this spring, baseball did appear to be out of control. Hits were near record lows. Strikeouts were at record highs. Pitchers were so dominant this spring that by mid-May — less than seven weeks into the season — they had already racked up well more than a typical season’s worth of no-hitters. And spin was at the center of it.

The changes in spin rates — measured using data from high-speed cameras that track every pitch of every game — are the most direct evidence that substances like Spider Tack were a significant factor in the dominance of pitching in the opening weeks of the season.

These materials allowed pitchers to grip the ball so well that they were able to generate far more torque on pitches, which in turn allowed them to spin the ball faster, making it harder to hit.

What’s changed

Typically, walks become somewhat less common as the season progresses. In 2021, walks increased after June 15 for the first time in decades:

The share of at-bats ending in strikeouts dropped to 23 percent:

Together, these contributed to the biggest increase in on-base percentage since at least 1990:

To measure the effect of the new rules on pitchers, The New York Times examined data from every fastball from 2017 to 2021, about 1.7 million pitches in all, and compared the change in spin rates in previous seasons with the rates in 2021.

In a typical season, a pitcher’s spin rate doesn’t change much: The rate on a fastball in May is usually close to the one on his fastball in September.

But this season, when even old-fashioned concoctions like a combination of rosin (which is legal) and sunscreen (which isn’t) came under scrutiny, most pitchers’ spin rates decreased after June 3. Of the 131 pitchers in our data set — pitchers who had thrown at least 150 fastballs since June 15 — fastball spin rates fell for all but 29 of them. And a handful of pitchers’ spin rates changed drastically, including nine whose fastballs lost 200 revolutions per minute or more.

Pitchers with biggest decreases

These are the pitchers whose spin rates on fastballs fell the most. (Some of these pitchers have openly discussed the effect of sticky substances, but several things — like injuries, changing pitching strategies or simply random poor performance — can account for changes in spin rates for individual pitchers.)

One caveat worth noting: There are many ways to identify which pitchers have been affected the most, and none are perfect. We could measure the simple change in spin rate before around the time of the ban, as we did above. We could measure this as a percentage, which may identify some pitchers whose fastballs were affected significantly even if they threw at lower speeds. Or we could measure change accounting for velocity of the fastball, since faster pitches naturally spin more.

Each of these methods yields a slightly different list. But no matter how we measured, these pitchers were at or near the top of it. (Each of the 10 players shown above ranked in the top 13 all three ways we measured.) Here’s how all the pitchers in our data ranked based on three different ways of comparing fastball spin changes:

Or use the tool below to see how spin rates changed for any pitcher in our analysis. (To be included, a pitcher must have thrown at least 150 fastballs before June 3 and at least 150 fastballs since June 15.)

Pitchers’ paradise

Players and officials have rarely raised eyebrows at offenders in the past. The rules prohibiting foreign substances have been routinely ignored. In the case of gripping substances — rather than old-fashioned lubricants used strictly to create unpredictable movement — pitchers have said having a good grip on the ball makes it safer for batters.

When asked about the effects of the rule changes, Rob Manfred, the commissioner of Major League Baseball, focused on the positive effects it has had on the game’s offense.

“Enforcing our rules is really important — they’re on the books, they should be enforced,” he said, calling the changes in play “very promising.” He was particularly pleased there had been no increases in batters hit by pitches — a point that he has made before and that has been backed by data showing batters have been less safe in this era of sticky substances.

“Those are all huge positives for us,” Manfred said.

Cole, the Yankees pitcher, has made no secret of his displeasure with what he perceived as uneven enforcement of the rules. Ahead of the All-Star Game last week, he echoed those complaints, saying, “There was no real legislation on the customs and practices that were going on.”

Cole and other pitchers have had to adjust quickly. “In terms of what’s been going on, it’s been a challenge to do it in the middle of the season,” he said. “But as players, we’re here now, we’re adjusting and I think we’re better for it in the long run.”

As clear as the changes have been in the data, not every major league batter has noticed.

“I can’t notice it, I can’t,” said Joey Wendle, the All-Star infielder for the Tampa Bay Rays. “I know everybody wants to hear yes, but to be honest, no, I really can’t tell a specific difference.”

What 200 r.p.m. is worth

A pitcher’s fastball going from 2,600 revolutions per minute to 2,400 might not seem like much, but that much spin can account for an extra inch of movement on a fastball — and significantly more for some pitchers — said Michael Fisher, founder of Codify, a company that provides customized analytics to dozens of major league pitchers. And in baseball, an inch can mean the difference between a three-run home run and an inning-ending double play.

“I’m the last guy to pooh-pooh an inch of movement when a bat is three inches wide,” he said.

On top of that, the extra spin that pitchers can get using sticky substances can confound hitters who have built up a lifetime of what Don Teig, a consultant who has worked with major league teams on the role that vision plays in maximizing motor performance, calls “visual memories.” Those are built-up ideas about what different kinds of pitches look like in the fraction of a second a batter has to make a decision.

The extra movement from sticky substances can render those memories useless.

“Does this look like a split-finger fastball?” Teig said. “Does it look like a curveball? All these things are being decided at that moment of truth.”

“You’ve told yourself visually where that ball is going in less than 0.2 seconds,” he said.

With those extra rotations, “the ball’s not going to wind up there.”