Toronto Blue Jays reliever Tim Mayza will undergo Tommy John surgery to repair a torn ulnar collateral ligament in his left elbow.
The news comes a day after Mayza dropped to his knees in pain after delivering an awkward pitch that sailed behind New York Yankees batter Didi Gregorius.
Mayza clutched his pitching arm and covered his face with his right hand as concerned teammates gathered around him at the mound. He left the field with a team trainer.
Friday's game marked Mayza's team-high 68th appearance of the year, tied for fourth most in the American League, though he has had at least two days off after his previous four appearances. He is 1-3 with a 4.91 ERA.
Information from The Associated Press was used in this report.