Matt Harvey has been diagnosed with a partially torn ulnar collateral ligament in his pitching elbow and has been placed on the disabled list.
Surgery has not been ruled out and if Tommy John surgery is required, he could miss the entire 2014 season.
Harvey was sent to a doctor after complaining of fatigue and mentioning discomfort following a 102-pitch start Saturday.
Harvey has swelling, but had not been experiencing pain in the elbow before his last start.
Via Adam Rubin/ESPN