Joe Nathan, 40, will undergo Tommy John surgery after being diagnosed with tears of the ulnar collateral ligament and flexor pronator in his right arm.

However, the Detroit Tigers reliever isn't currently planning to retire.

"My mindset is to do what I need to do, to work my butt off to get back in this game," Nathan said. "I also know that if it doesn't work out, I have nothing to complain about. I played baseball till I'm 40 years old."

The tears occurred during his rehab appearance Wednesday for Triple-A Toledo. Nathan had been on the 15-day disabled list for the past two weeks with an elbow flexor strain.