Maine, 29, is making $3.3 million this season and is arbitration-eligible, meaning the organization is near-certain to cut him loose by the non-tender deadline in December, freeing Maine to sign elsewhere.
Maine was a 15-game winner in 2007, but his velocity did not return after he had surgery in September 2008 to remove a bony growth from his right shoulder socket. Team officials attributed the diminished velocity to nerve irritation caused by scar tissue from the procedure.
The current procedure involved removing scar tissue, and Maine should be ready for spring training, a team official said. However, it remains to be seen which team's spring-training camp Maine will be in.
The latest procedure was performed by Dr. Michael Ciccotti in Philadelphia, near where Maine's agent, Rex Gary, is based, rather than by doctors from the organization's Manhattan-based Hospital for Special Surgery.
Maine went 1-3 with a 6.13 ERA in nine starts this season. His final appearance came at Nationals Park on May 20, when he was pulled after five pitches against his will. After Maine expressed displeasure with his removal, pitching coach Dan Warthen labeled Maine in denial, calling him a "habitual liar" with respect to his shoulder's health.