It's Bergmann's second injury this season. He missed more than month of action because of a sore right elbow.
"We have to see how he feels [on Wednesday] before we could talk about the next start," manager Manny Acta said.
Bergmann hurt the hamstring running the bases in the top of the third inning. With Bergmann on second base and two outs, Ronnie Belliard singled to center fielder Aaron Rowand. Third-base coach Tim Tolman decided to send Bergmann home, but as he was rounding third, Bergmann felt tightness in the hamstring. He kept going and Rowand was able to throw Bergman out at the plate to end the inning.
Tolman acknowledged that he made a mistake sending Bergmann home, but said that Bergman is not a typical pitcher when it comes to running the bases.
"Bergy is one of those pitchers that takes pride in baserunning. He gets good secondary leads," Tolman said. "We know that Rowand has a great arm. It was the wrong place at the wrong time to send him. ... It was a poor decision."
Bergmann came out to pitch in the bottom of the third inning, but had problem with his follow-through on the mound. He gave up a home run to Jimmy Rollins, and after Bergmann walked Chase Utley with one out, Acta, athletic trainer Lee Kuntz and pitching coach Randy St. Claire went to the mound to see what was wrong. About 30 seconds later, Bergmann left the game.
"After I walked Utley, that could have been really stupid to stay out there and tough it out. [Ryan] Howard could have done some real damage to me at that point," Bergmann said.
Bergmann lasted 2 1/3 innings and gave up two runs on two hits.
"I think the best thing for us to do is treat it and see how it is tomorrow. I'm not aware of any decision either way," Bergmann said. "I'm not the type of person to take myself out of the game unless it was really that bad. I continued running. I slid. I came back in the dugout. It basically felt like a little charley horse. I wanted to go back out there."
If Bergmann is not able to pitch on Sunday, the Nationals would most likely have to call up two pitchers for the four-game series against the Mets. They already plan to bring up one pitcher for Saturday's doubleheader because right-hander Jason Simontacchi is on the disabled list with a sore right elbow. Left-hander John Lannan and right-hander Joel Hanrahan are candidates to pitch in that game.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.