Terrell Owens, who has placed himself among the NFL's all-time leading receivers with plans to play a 16th season, has undergone surgery to repair a torn anterior cruciate ligament in one of his knees following a previously undisclosed injury this offseason, according to sources familiar with the injury.

Owens, 37, was unavailable for comment but sources said the surgery by noted orthopedist Dr. James Andrews occurred within the past month.

One source said Owens was hurt while on site taping a television show for VH1.

Another source said Owens tore the ACL during a personal workout but other sources could not confirm the cause of injury. His agent, Drew Rosenhaus, also was unavailable for comment Sunday evening. His brother and partner in the agent business, Jason Rosenhaus, said, "I don't like to deny stories or confirm or deny anything. It's really something for Drew (to address)."

Rosenhaus issued a denial to an ESPN inquiry last month about Owens' injury. Other sources close to Owens ignored specific inquiries Sunday night.

Owens has never made reference to an ACL injury on Twitter, where he has an active account.

Owens' 2010 season for the Cincinnati Bengals came to an end when he tore meniscus cartilage in his left knee Dec. 19 against the Cleveland Browns in week 14. Dr. Andrews surgically repaired Owens' meniscus on Dec. 20.

Sources said while Owens did tear an ACL with the new injury, he suffered no other damage to the knee in question and with intensive rehab he conceivably could return within six months, or around mid-to-late November, in a best-case scenario.