KANSAS CITY, Missouri (AP) ― Mariano Rivera tore a ligament in his right knee while shagging balls during batting practice Thursday night, casting a pall over the New York Yankees even before their 4-3 loss to the Kansas City Royals.

The 42-year-old right-hander’s leg caught on the field where the grass meets the dirt, causing his knee to buckle. Rivera fell into the outfield wall and down on the ground, where he grimaced in pain while teammates and training staff ran out to see him.

Rivera was carted from the field and taken for an MRI exam, and Royals head physician Dr. Vincent Key diagnosed a torn ACL after looking at scans of the knee.

“I thought it wasn’t that bad, but it’s torn,” Rivera said after the game, pausing several times in the Yankees clubhouse to compose himself. “Have to fix it.”

Rivera said that he never gave a thought to getting hurt while chasing balls during batting practice. It’s something that he’s done his entire career to keep in shape.