Right guard Randy Thomas fractured his right fibula in Sunday's 35-7 win over the Dallas Cowboys. The injury will end Thomas's 2005 season.
Thomas is expected to undergo surgery on his leg on Monday evening and then be placed on injured reserve.
"We will miss him," head coach Joe Gibbs said. "He has been a real leader for us. I think he has had as good of a year as I remember a guard having."
Added H-back Chris Cooley: "That's a tough injury, especially for it to happen near the end of the game like it did. We have guys that will have to step in. We'll have to fill it up and play tough."
Thomas sustained the injury in the fourth quarter of the game. His leg was rolled on by a teammate while there was a scramble for a fumble.
Thomas was upbeat in the locker room after the game.
"I'm always positive," he said. "I just have to stay up. I have to keep my spirits up. These guys are on a high after this win. We are going to play the Giants. We have to keep winning."
Thomas was replaced in the lineup by veteran offensive lineman Ray Brown.
Gibbs said after the game that he expects Brown to step into the starting lineup in place of Thomas.
"I think Ray will have to go in for us," Gibbs said.
Brown said after the game that he is ready to pick up the slack for Thomas.
"I feel pretty good," Brown said. "I am healthy and I think I can go out there and play a few weeks of pretty good football.
Added Brown: "We are going to try and reload and get ready for next week. Obviously we are going to miss Randy, but with any ball club over the course of 16 games there will be people sliding in and out. There are two weeks of the regular season left and I think I can step in and help out."
Thomas was part of an offensive line that has been dominant in recent weeks. On Sunday against the Cowboys, the Redskins' offensive line helped Clinton Portis rush for 112 yards and did not yield a sack.
After the injury, Thomas had to be carted off the field. As he exited, he raised his fists high in the air to acknowledge the FedExField crowd, who stood in applause of the seventh-year offensive lineman.
"We just beat Dallas," Thomas said. "We swept them for the first time in a long time. I directed that to the fans for sticking by us through everything."