[BigAsh]

Mo out for the year with torn ACL???....

Mariano Rivera's season -- and perhaps his career -- may have ended during batting practice on Thursday. The initial diagnosis on Rivera's right knee is a torn anterior cruciate ligament, Yankees manager Joe Girardi told reporters after Thursday's game in Kansas City. Rivera is expected to get a second opinion.

"If that's what it is, that's about as bad as it gets," Girardi told reporters.

The 42-year-old had hinted before the season that the 2012 season may be his last.

Rivera injured his right knee during batting practice before Thursday's game at Kauffman Stadium. Rivera was examined by Royals doctor Joe Noland and Yankees trainers before being sent to KU MedWest for an MRI.

Girardi and bullpen coach Mike Harkey picked Rivera up off the ground and carried Rivera to a cart to be taken off the field.

MLB Network showed live footage of Rivera being taken off the field. Rivera was slumped against the center-field fence during Yankees batting practice before Girardi and Harkey helped him to the cart.

YES Network had video footage of Rivera shagging fly balls that showed a ball hit by Jayson Nix that went over Rivera's head and he jumped to try to catch it, but it appeared his right knee buckled and he fell to the ground.

They also showed the reaction of Nix and Alex Rodriguez. Rodriguez, who was behind the batting cage could be seen saying, "Oh, my God. Oh, my God."

Rivera has shagged foul balls throughout his career in the big leagues. Considered one of the team's best athletes, Rivera has often joked that he'd like to come back as a centerfielder after retiring as a pitcher.