Watch Injury Video : Mariano Rivera ACL Injury

New York Yankees manager Joe Girardi says closer Mariano Rivera has a torn right knee ligament, an injury that could potentially end his career. The 42-year-old right-hander was carted off the field after twisting his right knee shagging .Mariano Rivera drifted back to the outfield wall, just like he'd done in batting practice so many times before, baseball's greatest closer tracking down another fly ball with childlike joy. Everything changed before anybody .Mariano Rivera -- the greatest closer in baseball history -- could be done for ever after tearing his ACL in a freak injury Thursday Mariano Rivera drifted back to the outfield wall, just like he'd done in batting practice so many times before, baseball's greatest closer tracking down another fly ball with childlike joy. The Yankees' 12-time All-Star caught his cleat where the grass .Mariano Rivera was carted off the field after twisting his right knee shagging fly balls during batting practice Thursday. / GETTY IMAGES KANSAS CITY, MO. — Yankees closer Mariano Rivera was carted off the field Thursday after twisting his right knee .Manager Joe Girardi said Mariano Rivera tore the ACL in his right knee, an injury that could potentially end his career. Rivera injured the knee while shagging balls near the outfield wall during batting practice before the Yankees' 4-3 loss at Kansas .New York Yankees closer Mariano Rivera has been carted off the field after hurting his right knee while shagging fly balls during batting practice before Thursday night's game at Kansas City. Baseball's career saves leader was tracking