NEW YORK -- The pitcher the Mets put in charge of happy endings 2 1/2 years ago has come to an unhappy and premature ending for this season -- perhaps for his career.

Billy Wagner, shut down since the first days of August, requires reconstructive surgery of his left elbow that will prevent him from pitching in the big leagues until late next season, if then. And, given his unwavering intention to retire after the 2009 season, the Mets closer may be permanently closed for business.

An examination via magnetic resonance imaging detected tears in the medial collateral ligament in Wagner's elbow and the flexor pronator, a muscle in the forearm, Monday and led the Mets doctors to recommend Tommy John ligament replacement surgery for the 37-year-old pitcher who has the sixth-most saves in big league history and who still was throwing with almost characteristic velocity when he pitched most recently, on Aug. 2.

But the condition of Wagner's left arm seemingly has deteriorated since mid-July. And now the Mets, in position to win the National League East championship for the second time in three years, know for certain what some had suspected for weeks -- that Wagner will be unavailable for the final weeks of the regular season and for whatever comes thereafter.

Wagner is to undergo surgery this week. A tendon from elsewhere in his body will be harvested and used as a replacement for the damaged ligament. Pitchers generally require a year of recovery and rehabilitation. Position players typically require significantly less time. Often a pitcher's velocity is compromised by the procedure. And Wagner, though he did rely more on offspeed pitches this season than in the past, still was a power pitcher -- a premier power pitcher.

His need for surgery means the Mets will go forward with a mix-and-match bullpen, a bullpen by committee with Luis Ayala serving a committee chairman. He has converted five of six save opportunities since the Mets acquired him from the Nationals on Aug. 17. And the bullpen had had a run of effective pitching of late -- one run in the most recent 23 innings. But it struggled mightily prior to that unexpected improvement.

"I'm very surprised and very sorry for Billy," manager Jerry Manuel said. "It does make it more difficult for us, But we'll get it done."

The surgery also means Wagner's pursuit of his 400th career save -- he has 385 -- has been suspended, perhaps permanently. The projected absence suggests the Mets will have re-think their plans for the 2009 season. Mets general manager Omar Minaya, faced with replacing other prominent players after this season, indicated Monday that he hadn't anticipated finding a new closer for next season, even though he acknowledged knowing as early as the first days of August that Wagner had torn a ligament.

"The tear is now big enough that the doctors are recommending so-called Tommy John surgery," Minaya said during a conference call Monday.

Minaya said an MRI that day had detected the tear but that Wagner and the team thought there was a chance he could pitch through the pain.

"There's a lot of guys who pitch with tears, especially when you're 37 years old," Minaya said. "Surgery was always a possibility in case things did not get better." Minaya also said Monday that he wouldn't be surprised if Wagner returned to pitch for the Mets next season. He characterized the pitcher as a competitor and noted Wagner had designs on putting his career saves total at least 400.

"I think if he wants to pitch, he will have the opportunity to pitch," the general manager said.

Had injury not interfered this summer, Wagner might have reached 400 saves this season and thereby ranked fifth all-time in the ultimate measure of closers' production. He had converted 27 of 34 save opportunities in the Mets' first 110 games. Before injuries undermined his availability, he assumed he would reach 400 next season and perhaps approach the 424 saves that rank former Mets closer John Franco fourth all-time behind Trevor Hoffman (552), Lee Smith (478) and Mariano Rivera (476).

Whether Wagner would abandon his plan to retire -- he has held to it steadfastly since he signed with the Mets following the 2005 season -- to pursue 400 saves and to be part of a contending team in 2010 is an imponderable at this point. The closer didn't return voice mail messages left on his cellular telephone Monday. The Mets said he was likely to be at Shea Stadium on Tuesday.

Wagner's contract -- four years for $43 million -- expires after the 2009 season, but the Mets hold an option for 2010 for $8 million, or a $1 million buyout. The money is not unimportant to him. Wagner wants to build a new home in Virginia for his wife and four children and maintains an in-season home in Greenwich, Conn. But he has said repeatedly he wants to be home in Virginia after the 2009 season. He has said it casually, kiddingly and quite seriously.

"Four years, and I'm done," he said during Spring Training 2006, his first camp with the Mets.

His unavailability is consistent with what the Mets have experienced since the middle of Spring Training. They have played the entire season without Orlando Hernandez, most of the season without Moises Alou and large chunks of the season without Pedro Martinez, Ryan Church, Luis Castillo and Matt Wise, each of whom had been expected to make significant contributions. Now they are without starter John Maine and Wagner, and concern about Martinez's health exists.

Wagner endured a series of arm problems this season. He experienced stiffness in his left shoulder in his second appearance after pitching one inning in the All-Star Game. And when he was assigned to the disabled list on Aug. 5 -- retroactive to Aug. 3 -- the reason given by the club was a strained muscle in his left forearm -- despite the awareness of the tear. Not until he threw in simulated game conditions in Pittsburgh on Aug. 16 did he speak publicly of pain in the elbow.

The Mets had anticipated his return two days later, even after watching him throw to batters. They were surprised -- and a tad miffed -- that he had told reporters of the pain without alerting the club.

"I wouldn't say I'm ready," he said that day.

He was to be examined on Aug. 17 at his home and then in Manhattan the following day.

"I'm guessing he'll say the elbow is inflamed and that once I get rid of the inflammation, I'll need some time to throw and get everything else up to speed," Wagner said after throwing then.

He took the pain matter-of-factly, and then his shoulder stiffened in Cincinnati July 20.

"I'm old," said Wagner, who turned 37 five days later. "I'm supposed to hurt."

He had struck out the side in the 10th inning that day.

"I should hurt more often," he said.

Wagner seemed to make progress last week when he threw at Shea Stadium while the Mets were in Milwaukee. But the elbow again was tender when he threw following the first game of the Mets' doubleheader Sunday.

Before he threw, he said, "I feel like I'm as good as I'm going to get."

He was right.