"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.
Wanna thank all my fans for their prayers n concerns I'm in good spirits n will be returning to field as quick as possible. #billsmafia #28â CjSpiller (@CJSPILLER) September 24, 2012
Follow Marc Sessler on Twitter @MarcSesslerNFL.