Johan Santana (pectoral) exits early

ATLANTA -- New York Mets left-hander Johan Santana left Thursday's 4-2 victory against the Atlanta Braves after five innings, feeling tightness underneath his left arm. A team spokesman announced Santana had a strained pectoral muscle.

"I came back in to stretch it and the pitching coach came in and said he's not going to take any chances and took me out of the game," Santana said. "I just came in to stretch and go back out."

Pitching coach Dan Warthen said letting Santana continue wasn't an option, given that Santana was one day past the one-year anniversary of elbow surgery.

"In that inning you saw the velocity dropped pretty sizably," Warthen said. "With the elbow surgery last year, you're not going to take any chances with Johan."

There actually was a discrepancy after the game about what ailed Santana. Manager Jerry Manuel initially pointed to the biceps to describe where the trouble occurred. And Warthen ominously said: "He felt his shoulder wasn't right. Somebody said pec. I don't know. I'm really not at ease."

Santana indicated this was the first time he had difficulty with the chest muscle. He suggested the issue surfaced facing the second batter of the bottom of the fifth inning, Melky Cabrera. Warthen said Santana indicated to him it started during the warm-up pitches that inning.

Santana was credited with the win after throwing 65 pitches and departing with a 2-1 lead, and he avoided losing four straight starts for the first time since May 18-June 3, 2004 with Minnesota. He allowed one run and three hits while walking one and striking out three. The Mets beat the Braves to avoid getting swept in the four-game series at Turner Field.

"It just progressed," Santana said. "It's not something that happened on one pitch."

Santana did not believe it was necessary to go to New York for tests. He planned to accompany the team to Chicago for Friday's series-opening matinee against the Cubs at Wrigley Field.

If Santana does not make his next start, right-hander Dillon Gee and left-hander Pat Misch would be options. There have been rumblings Gee would be called up anyway after he completed his Triple-A season with a 13-8 record, 4.96 ERA and Buffalo modern-era-record 165 strikeouts. Misch was just bumped from the rotation to make room for 20-year-old rookie Jenrry Mejia's start Saturday against the Cubs.

"We'll see how I feel the next couple of days and go from there," Santana said. "I'll be all right. … I definitely want to end the season pitching. That's the way I want it to, and that's the way it will be. But, at the same time, we're going to keep our eye on it and make sure everything is fine. As of right now, I feel fine. So we'll see how it feels tomorrow. Once [trainer Ray Ramirez] started stretching it, it was fine, but I was out of the game."

Adam Rubin covers the Mets for ESPNNewYork.com. You can follow him on Twitter. Information from The Associated Press was used in this report.

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