Though final tests results aren't in, coach Chan Gailey all but ruled out Spiller from playing next week, when the Bills travel to play Cincinnati.
"I can't imagine him playing this week," Gailey said. "We'll have to see how long it lasts."
In becoming the NFL's final team to win this season, the Bills (1-8) also lost defensive lineman Spencer Johnson to a hamstring injury in the second half. Gailey would only say that Johnson's injury is less severe than Spiller's.
Spiller, the rookie first-round pick, was hurt after he was hit along the sideline and pushed out of bounds by Detroit's Vinny Ciurciu after returning a punt 29 yards with 9½ minutes left in the second quarter.
Spiller got up on his own and made his way across the field without any indication he was hurt. Shortly afterward, he was escorted by a trainer to the Bills locker room and never returned.
Spiller was returning punts in place of Roscoe Parrish, who broke his wrist last week in a 22-19 loss to Chicago.
Selected ninth overall out of Clemson, Spiller has spent much of the season in a backup role. He has 41 carries for 164 yards rushing, and 18 catches for 81 yards and a touchdown.
Quinton Ganther, who was signed this week by Buffalo, took over the backup role behind Fred Jackson.
Copyright 2010 by The Associated Press