Loeffler broke a bone in his lower back on the hit in the second quarter and is out for the season.
Washington's Stephen Bowen and Seattle's K.J. Wright were each fined $15,000 on Friday for roughing the passer penalties last Sunday. Neither of the players' hits were called as penalties during the game.
Bowen was fined for lowering his head and striking Seahawks quarterback Tarvaris Jackson with his helmet in the fourth quarter. Wright's was a result of hitting Redskins quarterback Rex Grossman in the neck area in the second quarter.