After all that arduous rehab work, Johan Santana's left shoulder has failed him again.

And now he must decide whether he has the stomach for another grueling comeback with a successful return not a sure thing.

Either way, Santana may have thrown his final pitch for the New York Mets.

The team said Thursday that the two-time Cy Young Award winner probably has re-torn the anterior capsule in his left shoulder and likely will need a second operation that would sideline him for the entire season. Santana missed 2011 following his first shoulder surgery.

"I am not a doctor, nor am I a medical historian, but these injuries are very difficult to recover from after one surgery, and I'm not sure what the history is of recovery from a second more or less identical surgery," general manager Sandy Alderson said on a conference call.

New York owes the 34-year-old left-hander $31 million more as part of the $137.5 million, six-year deal he signed before the 2008 season, and Alderson said the remainder of the contract is not covered by insurance.

The Venezuelan pitcher had surgery on Sept. 14, 2010, and did not make it back to the majors until last April 5. He went 6-9 with a 4.85 ERA in 21 starts last year and threw the first no-hitter in franchise history on June 1 against St. Louis.

Santana threw a career-high 134 pitches that night in his second consecutive shutout, but was 3-7 with an 8.27 ERA after that, including 0-5 with a 15.63 ERA after throwing eight scoreless innings against the Los Angeles Dodgers on June 30.

He went on the disabled list for three weeks because of a sprained ankle and didn't pitch after Aug. 17 because of lower back inflammation.

Santana hasn't pitched in any exhibition games during spring training because of arm weakness, and he threw his last bullpen session in early March without the team's permission.

"We don't know when it happened, how it happened," Alderson said. "But what we do know is that at some point symptoms appeared and they worsened rather than improved."

Peter Greenberg, the pitcher's agent, said Santana didn't have any comment yet.

Alderson said an MRI in New York on Wednesday with Dr. David Altchek showed the probable re-tear, and that noted orthopedists Dr. James Andrews and Dr. Lewis Yocum concurred with the diagnosis on Thursday after reviewing the MRI.

"Johan will remain in New York over the Easter weekend to decide on next steps," Alderson said. "A second surgery is a strong possibility. If this diagnosis proves to be correct, I think in all likelihood Johan will be lost to the Mets for the season."

Based on reporting by the Associated Press.

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