Baseball's foreign substance reckoning is here. Major League Baseball, after decades of looking the other way, is poised to begin cracking down on pitchers using foreign substances after a fact-finding mission earlier in the 2021 season determined the problem is widespread enough to warrant intervention. Team owners voted to move forward with the crackdown last week. In the days since, several notable pitchers have shown reduced spin rates, a trait that can be enhanced with the right sticky stuff. 

Yankees ace Gerrit Cole, who was recently accused of doctoring baseballs in a lawsuit, was down about six percent across the board with his spin rates during his most recent start Thursday, when he allowed five runs in five innings against the Rays.

Here are Cole's average spin rates by start this season (these are all pitch types lumped together):

Gerrit Cole's average spin rate was down noticeably Thursday. Baseball Savant

"Is it a coincidence that Gerrit Cole's spin rate numbers went down [Thursday] after four minor leaguers got suspended for 10 games?" Twins third baseman Josh Donaldson told reporters, including The Athletic's Dan Hayes, referring to MLB's recent crackdown on foreign substances in the minors. "Is that possible? I don't know. Maybe. At the same time, with this situation, they've let guys do it."

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Cole has not spoken to reporters since Thursday's post-start scrum, before Donaldson made his comments (Cole is scheduled to speak Tuesday, the day before a start as usual). Yankees manager Aaron Boone essentially dismissed Donaldson's comments on Sunday though.

"I don't make much of it," Boone told reporters, including NJ.com's Brendan Kuty, prior to Sunday's game. "Gerrit as well of our staff members, I believe, are mostly above board and they'll be able to handle the situation in the right kind of way and it's not going to affect the kind of pitchers they are."

A few hours before Boone was asked about Donaldson's comments, Dodgers righty Trevor Bauer, who has flaunted his increased spin rates since joining the Reds two years ago, showed reduced spin during his start against the Braves. Bauer's spin rates were down about 10 percent across the board. He allowed three runs on six hits and four walks in six innings.

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Here are Bauer's average spin rates by start this season (again, these are all pitch types lumped together):

Like Cole, Trevor Bauer's average spin rate was down considerably in his last start. Baseball Savant

Without explicitly saying his name, Bauer accused Cole and the Astros of using foreign substances to improve spin rates a few years ago. "If only there was just a really quick way to increase spin rate. Like what if you could trade for a player knowing that you could bump his spin rate a couple hundred rpm overnight...imagine the steals you could get on the trade market! If only that existed..." Bauer wrote in a tweet.

Bauer later wrote that he knew he could increase his spin rate 400 rpm with foreign substances, and lo and behind, his spin rates increased roughly 400 rpm when he joined Cincinnati the next year. The 2020 NL Cy Young winner has not been subtle about it. Momentum, a company co-founded by Bauer, even sells "Legalize Pine Tar" merchandise on its website.  

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"I don't know," Bauer told reporters, including Jorge Castillo of the Los Angeles Times, when asked about the drop in his spin rates Sunday. "Hot, humid day in Atlanta. I just want to compete on a fair playing field. I'll say it again. That's been the whole point this entire time. Let everyone compete on a fair playing field. So if you're going to enforce it then enforce it. And if you're not then stop sweeping it under the rug, which is what they've done for four years now."

When asked whether he can be the same pitcher he was in 2020 if MLB cracks down on foreign substances, Bauer said, "Go look at the 2018 numbers and tell me what you think." Bauer was excellent in 2018 (2.12 ERA in 175 1/3 innings), though that is more or less an admission he is using foreign substances. The implication is he didn't use them in 2018 but is now, which matches up with the data on his spin rates.

David Samson broke down MLB's foreign substance issue on Monday's Nothing Personal with David Samson. Listen below:

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Lucas Apostoleris of Baseball Prospectus and data-savvy baseball fan Max Bay have both written that single-game spin rates are to be taken with a grain of salt, especially since MLB switched from Trackman to Hawk-Eye for Statcast last year. Hawk-Eye is prone to data capture errors with spin from time to time, and it takes time to be sussed out. The data is reliable, but not perfect.

Given what we know -- Cole has been credibly accused of doctoring baseballs and Bauer essentially confirmed it with his comments Sunday -- the decline in spin rate right as MLB prepares to crack down on foreign substances is notable. We can't say for certain that the two are related, there is always a chance this is a big coincidence, though at this point there's enough here to warrant further attention moving forward, both from fans and MLB's foreign substance police.