Coach Sean McDermott said after Thursday's game that Williams suffered a hamstring injury against the Vikings, Mike Rodak of ESPN.com reports.
Williams was easily Buffalo's best rusher Thursday as he took four carries for 39 yards -- including a 17-yard scamper. Unfortunately, he suffered a hamstring injury during the course of the game, but McDermott did not immediately elaborate on the severity of the ailment. The Bills figure to have a further update on Williams' hamstring injury in the near future.