Washington Nationals ace Max Scherzer, hat on the ground, unbuckled his belt as umpires stood around him. Oakland Athletics reliever Sergio Romo walked off the mound and pulled down his pants. New York Mets star Jacob deGrom laughed as he held out his hat for on-field examination.

That was the scene across baseball in June as MLB began its much-anticipated crackdown on so-called sticky stuff, the increasingly tacky substances that have allowed pitchers in recent years to hurl baseballs that spin faster and faster, causing them to dive and slide through the strike zone in ways batters have never seen.

Before the spectacle of on-field enforcement even began, word of its arrival trickled out around June 3, as MLB made it known it planned to increase scrutiny amid record-high strikeout rates.

It appears to be working. Spin rates — or the number of revolutions per minute a baseball makes on its way to home plate — have decreased across the sport, according to a Washington Post analysis. Pitchers have said in recent weeks that it’s difficult to grip the ball, and the Post analysis shows that, too: Some pitchers appeared to be searching for grip — using rosin, trying to find sweat and licking fingers — behavior that suggests they are trying to adjust to this new reality.

Spin rate can be key to a pitcher’s success: A pitch thrown with the same velocity will move differently depending on how fast it spins, and a pitch with a higher spin rate often moves more sharply than one thrown with the same velocity but less spin.

The Post analyzed the spin rate, controlling for velocity, for nearly 2 million pitches, focusing primarily on fastballs, of more than 1,400 players from about 9,000 games from 2017 to 2021 — including almost 70,000 pitches since June 3. After climbing year over year, spin rates fell in the three weeks after June 3 to levels lower than in 2017, when the data first started being tracked reliably, according to a Post analysis of data published by Baseball Prospectus.

But the steep fall, combined with batters’ increased ability to make contact, appears to show that MLB’s effort has been effective in reducing pitchers’ advantage over hitters, at least in the short term — a noteworthy development amid historically anemic hitting. About 70 percent of the pitchers who threw more than 10 fastballs after June 3 saw a decrease in their average adjusted spin rates compared with earlier in the 2021 season, according to the Post’s analysis.

The rise of sticky stuff

MLB’s official rules have long barred players from altering the ball. For years, though, pitchers have flouted these prohibitions, honing creative methods to maximize movement and confound hitters.

Through it all, MLB enforced the rule sparingly. Umpires checked pitchers at the prodding of an opposing manager but rarely on their own. And those checks were infrequent, as everyone from MLB to teams to players tacitly agreed to look the other way.

Over the past decade, improved technology helped teams learn more about the way pitches move on the way to the plate and the forces that act on them as they do. Most notably, high-speed cameras, installed in many ballparks, allowed teams, increasingly run by data obsessives, to measure and learn to optimize spin rates.

As it became clear that better grip led to more spin, the substances themselves evolved. Spit and sweat led to sunscreen and rosin, which led eventually to substances such as Spider Tack, which was designed to help strength competitors hold huge concrete spheres.

The result: lots and lots of strikeouts. While the crackdown on sticky stuff has been cast by MLB as an attempt to “level the playing field,” it comes as baseball is desperately trying to close a growing gap between pitchers and hitters. The batting average across the majors in 2021 was .239 when MLB’s crackdown on the sticky stuff began June 21, the lowest it had been since 1968, after which MLB lowered the pitcher’s mound to help hitters. Not since that change have pitchers been so dominant.

There are other reasons for the disparity, including pitchers throwing with higher average velocity than ever. But that velocity is combining with climbing spin rates to give hitters less time to react to pitches that are often moving more than ever. The result has been 20 years of rising strikeout rates culminating in this year’s rate of 24 percent as of the day enforcement began June 21 — a number that means almost a quarter of all major league at-bats end in a strikeout now. Thirty years ago, it was 15 percent.

The crackdown

After last year’s pandemic-shortened season, MLB committed to cracking down on sticky stuff this season. It sent monitors to stadiums to collect game-used baseballs and tracked changes in spin rates using Statcast, state-of-the-art technology that allows for the collection and analysis of a massive amount of data.

Two months into the season, MLB outlined its findings: The use of foreign substances was prevalent and sometimes “brazen,” it said. It would respond, it said, by instructing umpires to inspect pitchers’ hats, gloves, hands and belts between innings and when they enter and leave the game, depending on the situation. It also announced progressive punishments beginning at ejection and a 10-game suspension for any pitcher found to be in possession of any foreign substance.

While word of MLB’s intentions to step up enforcement trickled out around June 3, the enforcement did not begin until June 21. Umpires began routine inspections that often include awkward chuckles and hurried belt checks. On Sunday, Seattle Mariners reliever Héctor Santiago became the first player ejected under the new policy, when umpires confiscated his glove after checking him. Santiago, who said he was simply using rosin, was suspended for 10 games, a disciplinary action he is appealing.

The impact of the crackdown is obvious not just in the data but in pitchers’ behavior on the mound and their comments afterward. The Post conducted a visual analysis of thousands of pitches using available footage of top-paid pitchers, including those who have spoken publicly about the use of foreign substances. The review included a total of six games per pitcher from the 2020 and 2021 seasons, both before and after the anticipated crackdown. The three games identified in the data before the crackdown capture the full range of each pitchers’ average spin rate and were used to establish common pitcher behaviors at the mound. The Post’s review relied on the home team’s MLB broadcast, which is not focused on the pitcher the entire game but provides a large sample of his movements to observe.

The analysis showed a dramatic increase in specific movements tied to improving grip by several pitchers, including behaviors not documented in games reviewed by The Post from before the crackdown.

Days before MLB’s efforts began, on June 8, New York Yankees star Gerrit Cole found himself in the center of the controversy when a reporter asked about Spider Tack and Cole struggled to answer.

Since then, he has looked different on the mound.

Last season, in a July game against the Baltimore Orioles, Cole pitched with an average adjusted spin rate, or a Bauer unit, of 26.27, his highest of that season. A Bauer unit is a pitch’s spin rate divided by its velocity, a commonly used equation for quantifying a pitch’s nastiness. It was named for Trevor Bauer, the Los Angeles Dodgers star who publicly accused pitchers of using sticky stuff to improve their performance — then increased his own spin rate and became one of the game’s most dominant pitchers. Bauer was accused in court records this week of assaulting a woman during sexual encounters. MLB placed Bauer on administrative leave Friday as police and MLB investigate the allegations, which Bauer’s lawyers have denied.

On June 16, two weeks after MLB announced its initiative, Cole’s average adjusted spin rate was 24.13, 6 percent lower than his average for the season so far, according to The Post’s analysis.

He acknowledged after his start that he was having trouble getting a consistent grip. On the mound that day, he looked for sweat on his arm or brow, licked his fingers, rubbed his pants and the ball or used the rosin bag more frequently.

(MLB)

“It’s so hard to grip the ball,” he told reporters. “For Pete’s sake, it’s part of the reason why almost every player on the field has had something, regardless if they’re a pitcher or not, to help them control the ball.”

Bauer has seen his spin rates drop, too. On June 12, his average adjusted spin rate dropped to 27.99, 5.5 percent lower than his average for the season so far. On June 23, available MLB footage shows him going to the rosin bag at least eight times. In two games The Post analyzed from before June 3, Bauer was not observed going to the rosin bag.

(MLB)

As the data shows spin rates dropping across the board, pitchers around the majors have been relatively open about their struggles to gain a consistent grip on the ball. Scherzer admitted he was getting sick of the taste of rosin on his hand in his first start after the new enforcement took effect, as he was having to rely on a combination of rosin and his own spit to grip the ball against the Philadelphia Phillies. At one point, Phillies Manager Joe Girardi asked umpires to check Scherzer’s hair for foreign substances because the Nationals ace was touching his head more than Girardi had ever seen.

“I was sick of licking my fingers and tasting rosin, and I couldn’t even get sweat from the back of my head because it wasn’t really a warm night. So for me, the only part that was sweaty on me was actually my hair, so I had to take off my hat to be able to try to get any type of moisture on my hand,” said Scherzer, who did not say what he used previously to help get that grip. His manager, Dave Martinez, has advocated for pitchers to have some grip and Scherzer has advocated for players to have a voice in the matter. The average spin rate on Scherzer’s pitches has dropped fewer than 100 rpm since June 3.

Tampa Bay Rays pitcher Tyler Glasnow said he used to use a combination of sunscreen and rosin to gain a grip but stopped before a June 8 start against the Nationals. Glasnow’s spin rate for fastballs dropped by 3.3 percent during the game compared with his 2021 season average. In comparison, MLB pitchers dropped an average of 2.3 percent after June 3.

In available footage, Glasnow was observed rubbing sweat from his forearm or wrist at least 20 times, licking his fingers and reaching for the rosin bag at least twice — behaviors not observed in games reviewed by The Post from the 2021 season before the crackdown.

(MLB)

He left his next game early with elbow trouble and was diagnosed with a torn ulnar collateral ligament and a strain to a tendon, an injury he said was caused by the fact that he stopped using his usual combination of sunscreen and rosin to improve his grip and was therefore putting more strain on muscles as he tried to compensate without it.

“I woke up the next day and was like, ‘I am sore in places I didn’t even know I have muscles in.’ I felt completely different. I switched my fastball grip and my curveball grip,” Glasnow told reporters. “I’ve thrown it the same way for however many years I’ve played baseball, and I had to change it.”

Boston Red Sox starter Garrett Richards, who has struggled since the ban came down, said it “changed pretty much everything for me.”

“I feel like I need to be a different pitcher than I have been for the last 9½ years,” he said.

The results of the crackdown are also being seen at the plate. Fewer at-bats after two strikes are ending in walks or strikes after June 3, a review of recent data shows, and more than 44 percent of them are ending with contact — up from 40 percent earlier in the season.

The future of spin

Since the chaos of the crackdown’s first games, pitchers have largely offered similar criticisms of the policy. Glasnow, Scherzer, Cole and others have urged MLB to incorporate player input into the new rules, and many of their colleagues have suggested a universal and MLB-approved sticky substance as a potential middle ground.

MLB is looking into that, an official said, while also developing prototypes for a pre-tacked ball.

Hitters, on the other hand, have shared more varied perspectives. Some say they want pitchers to be able to use some kind of substance so they don’t lose control and hit more batters. But others see the changes as necessary to making the game fair again.

“We were so stupid as hitters, saying: ‘Oh, yeah, it’s for control. We just don’t want them to hit us,’ ” the Chicago Cubs’ Kris Bryant said. “That was such a cop-out.”

About this story

The Post reviewed MLB footage and analyzed nearly 2 million pitches, focusing primarily on fastballs, from data provided by Baseball Prospectus since 2017, when spin rates started being tracked reliably. Details on The Post’s methodology, as well as summarized lookups on pitchers and teams, can be found on GitHub.

Jeremy Bowers, Jason Holt and Joe Fox also contributed to this report.