Jason Taylor suffered a sprained right knee in the second quarter of Saturday's preseason game against the Carolina Panthers.
It appeared Taylor had his right leg get tangled in a pile of players on a run play. Television replays showed him wincing in pain immediately after the play.
He was able to walk off the field with the help of athletic trainers. He was later carted into the locker room for X-rays, which were negative.
Taylor is scheduled for an MRI on Sunday. The team will update his status at that time.
It's unlikely that Taylor will play in next Thursday's preseason finale against Jacksonville. His availability for the Redskins' season opener on Sept. 4 against the New York Giants is in question.
After the game, Taylor traveled back to Washington, D.C., with the team for the MRI.
The Redskins had acquired Taylor in a trade with the Miami Dolphins on July 20 after Phillip Daniels suffered a season-ending knee injury.
Taylor, one of the NFL's elite pass rushers with 117 career sacks, was replaced by Demetric Evans.
He has 130 consecutive starts, which ranks seventh among active players.