Twins reliever Joe Nathan has been diagnosed with a torn ligament in his right elbow, leaving the team without a proven closer less than a month from Opening Day, according to an ESPN.com report. Nathan has a torn ulnar collateral ligament and will decide whether to have surgery within two weeks, the team said. The Minneapolis Star Tribune first reported the injury. The team announced Nathan has a "significant tear," but will not immediately opt for surgery. He will rest and rehab the elbow over the next one to two weeks, then determine whether he can pitch with the injury.