Bills quarterback Kelly Holcomb left the game with a severe concussion against Kansas City. Coach Mike Mularkey said he wasn't sure whether Holcomb would be able to start next week against San Diego, and Benson is scheduled to undergo an MRI exam Monday. Holcomb was hurt in the second quarter of a 14-3 win when he was sacked by Jared Allen. Holcomb fell backward and landed on teammate Mike Williams' leg, forcing the quarterback's head to snap back. He was on the field for a few minutes and looked groggy while trainers attended to him on the sideline. J.P. Losman took over, producing two touchdown drives in his first appearance since Holcomb was named starter following a 19-7 loss to New Orleans on Oct. 2.