Sharp said:That ship sailed in the mid-nineties when Mo had TJ surgery.
Mo never had TJ surgery... They opened up his elbow but his divine ligament had already fixed itself. The procedure wasn't completed
edit:
Michael recalled being in Fort Lauderdale the night Rivera hurt his elbow in the minors in 1992, recalled taking him to see Dr. Frank Jobe, who performed surgery on Rivera's elbow in August of that year.
"People think he had the Tommy John surgery but he didn't," Michael said. "The ligament was frayed and Dr. Jobe cleaned it up. At that time, Mariano wasn't a top, top prospect. He only threw 88 to 91 but we made the decision to protect him on the 40-man roster anyway that winter.
http://articles.nydailynews.com/200..._yankees-gm-gene-michael-tommy-john-surgery/2