(Renton, WA)  --  There's doubt over whether Seahawks tight end Luke Willson will play against Minnesota in this Sunday's wild-card playoff game.  Willson sat out yesterday's practice with a concussion.  He missed last Sunday's regular-season finale against Arizona after suffering the concussion in the St. Louis game the week before.  Should Willson miss the Vikings game, Cooper Helfet and Chase Coffman will be the only healthy tight ends available Sunday for Seattle.