New York Mets pitcher Noah Syndergaard has a partial tear of his right lat muscle and has been placed on the 10-day disabled list, the team announced on Monday.  Syndergaard underwent an MRI at the Hospital for Special Surgery on Monday and there is no time-frame for his return.

Syndergaard (1-2) allowed five runs on five hits in the first inning Sunday, a game the Mets lost 23-5. In the second, he threw a strike to Bryce Harper on his 38th pitch and grimaced while reaching for his right armpit.

Mets manager Terry Collins and the team trainer immediately came out, and Collins summoned reliever Sean Gilmartin.

"The preliminary diagnosis is possible lat strain," general manager Sandy Alderson said, "which may or may not be related to his previous complaint, which was in the biceps. So we'll just have to wait and see what happens tomorrow."

Syndergaard was not available to reporters in the clubhouse after game. Alderson said the pitcher was on his way to New York for a 7 a.m. appointment Monday.

Syndergaard was making his first start since April 20. The right-hander was a late scratch from his last scheduled outing Thursday against Atlanta due to biceps and shoulder discomfort in his pitching arm. But he threw a bullpen Friday, said he felt fine and refused an MRI.

"The recommendation was made by the doctor; it was precautionary. He felt strongly that he was fine," Alderson said. "We made sure that he threw again before he went out, so we could confirm that, and that's what happened.

"Would the MRI have disclosed a lat issue or reaffirmed some concern about the biceps? We'll never know."

Alderson said he spoke to Syndergaard after the game, but could not say whether he regretted refusing the earlier MRI.

"We didn't get into that," Alderson said. "I didn't think that was necessary at that particular time, so I think he understands now that there's something going on that needs to be examined."

After watching his bullpen, and then backup catcher Kevin Plawecki, get roughed up over the final 7 2/3 innings, a terse Collins said Syndergaard's issue Sunday was a different one than the biceps.

"It's not even close to the same area," Collins said. "This is his lat, nothing to do with his arm."

Collins later snapped at a reporter who said the Mets manager seemed upset.

"Ya think? What do you think?" he said.

Washington Nationals manager Dusty Baker, whose team set a franchise record for runs, said he noticed something about Syndergaard in the first inning.

"We could tell something was wrong," Baker said. "He was throwing the ball firm but it wasn't moving like usual. When you have a guy like that, you certainly have to jump on him."

The Nationals sent 10 batters to the plate in the first, getting five hits and two walks, one intentional.

"When you've got eight days' rest you feel stronger and you want to overpower," Mets catcher Rene Rivera said. "He was leaving the ball in the middle."

Rivera didn't notice anything wrong until the final pitch.

"Noah was grabbing, I guess his lat, and I ran out there and he didn't speak," the catcher said.