Seahawks RB Marshawn Lynch injured his back in warmups and did not play in Sunday's loss to the Browns.
Leon Washington got the start and rushed for 39 yards on seven carries. Justin Forsett had eight carries for 23 yards.
Lynch is the team's leading rusher with 239 yards in five games. He has two rushing touchdowns on the season and rushed for a season-high 98 yards in the team's last game.
It is unknown if Lynch will be forced to miss next week's game as well.