Astros general manager Ed Wade received the report Tuesday morning from Mark Rodgers, Hampton's agent. Wade said Dr. David Altcheck at the Hospital for Special Surgery in New York City found a full rotator cuff tear and a "big hole" in his rotator cuff.
"He's not to pick up a ball until January or February of next year and will not pitch in 2010," Wade said.
Hampton, 37, went 7-10 with a 5.30 ERA in 21 starts this year for the Astros, who signed him to a one-year, $2 million contract in the offseason. Various injuries, especially Tommy John elbow ligament replacement surgery, limited the left-hander to just 25 Major League starts from 2005-08.
Hampton said recently he also wants to have arthroscopic surgery on both knees at some point in the offseason.
"Obviously, he was trying to battle through all these issues that he's got and plus he's got the knees, and we haven't talked about that yet," Wade said. "It's unfortunate."
Wade said Hampton will likely join the team next week in Houston.
Brian McTaggart is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.