"It's tough, because we are playing good right now," Belliard said. "We are trying to win some games. I want to help this ballclub."

With one out in the top of the seventh inning and Atlanta reliever Jeff Bennett on the mound, Belliard hit a high chopper to shortstop Omar Infante, who didn't come up with the ball. Belliard pulled up lame halfway down the line but managed to limp to first for an infield single, his third hit of the game.

Manager Manny Acta and head athletic trainer Lee Kuntz came to Belliard's aid. Belliard was immediately taken out of the game and replaced by Kory Casto.

"It's a bad groin pull. It looks like he might be done for the year," Acta said.

With Belliard gone, it means that Aaron Boone and Casto will platoon at first base for the rest of this week. But starting Tuesday against the Mets, Dmitri Young will most likely be the everyday first baseman.

Belliard was the hottest hitter on the Nationals since the All-Star break with a .353 average in 133 at-bats.

This story was not subject to the approval of Major League Baseball or its clubs.