Bills coach Chan Gailey said after the game that Spiller didn't suffer a broken collarbone but would be out for a week or two. Gailey didn't know the extent of Spiller's injury.
"I don't believe it's long, long term," Gailey said, according to The Buffalo News. "If he misses a week, that's long for me. I think he's going to be out for sure this week, and then we'll see where he goes from there."
Spiller fell hard on his left shoulder and was carted off minutes later. Backup Tashard Choice took Spiller's place.
Before the injury, Spiller already had inflicted significant damage on Cleveland's defense, hauling in a 32-yard scoring strike for Buffalo's second touchdown and accounting for 16 yards on four carries. The Bills went into the game with starting back Fred Jackson still sidelined with a knee injury, but his return could come as soon as next week
UPDATE: Spiller issued the following tweet Sunday night.