2021 pitch doctoring controversy

[3] In 2009, professional strength athletes James Deffinbaugh and Michael Caruso began working on a substance that would allow weightlifters and bodybuilders to better grip the large, awkwardly-shaped lifting stones used during World's Strongest Man competitions.

In addition to strongman competitions, Spider Tack became popular in the wheelchair sports community, as the tackiness of the substance helped athletes maintain their grip on the wheels of their chair.

[5] MLB undertook an informal poll during the 2020–21 offseason, during which they found that a majority of field managers considered foreign substances to be the most urgent issue in the sport.

Meanwhile, his Yankees teammate Jameson Taillon admitted that he had tried Spider Tack while recovering from Tommy John surgery, but that he had struggled to pitch with the substance and thus no longer uses it.

Donaldson threatened to expose "an entire catalog of cheating videos" of pitchers that he believed to be using foreign substances, before telling reporters that he wanted umpires to check "every half-inning" for non-compliance.

"[13] Tyler Glasnow, a pitcher for the Tampa Bay Rays who openly admitted to using a mixture of sunscreen and rosin to improve his grip on the baseball, blamed the MLB crackdown on such substances for his season-ending ulnar collateral ligament injury.

[14] Nationals general manager Mike Rizzo called Glasnow "courageous" for admitting to using grip-enhancing techniques and criticized MLB for the sudden ban.

[15] On June 15, 2021, MLB issued a press release announcing new guidance regarding "a uniform standard for the consistent application of the rules, including regular checks of all pitchers regardless of whether an opposing club's manager makes a request."

Included in MLB's announcement was a mandate for routine, random checks of all pitchers by umpires in the Major and Minor Leagues, with any player found to have a foreign substance immediately ejected and suspended for 10 games.

[18] On June 27, Seattle Mariners left-hander Hector Santiago became the first player ejected under MLB's heightened enforcement, after umpires discovered a foreign substance on his glove.

Just before the ejection, Bumgarner appeared to have become frustrated after Bellino stared down the pitcher and held his hand for an abnormally long time during a foreign substance check.

Following the top of the third inning, when Bellino went to check the pitcher's hand, Bumgarner took a hard left so that home plate umpire Mark Ripperger could perform it instead.