Raiders right guard Mike Brisiel left Thursday's game against Dallas after injuring his knee on Oakland's first offensive play.
Brisiel stayed down for a couple of minutes after the play, though he walked off the field without any help. But the team later said he wouldn't return without providing additional specifics about his injury.
The guard also left the game at Houston on Nov. 17 with a knee injury. He was cleared after an MRI the following day.
Brisiel and left tackle Khalif Barnes are the Raiders' offensive linemen who have started every game this season.