Jackson had nine carries for 14 yards against the Rams before being injured. Jackson was hit low and stayed down on the field before being helped to the sideline. It is not clear yet whether the injury is to his knee or ankle, but he had to be driven back to the locker room.
Thus far in the 2012 season, Jackson has carried 106 times for 423 yards and three touchdowns. He has also caught 29 passes for 201 yards and one receiving touchdown.
The 31-year-old Jackson is a six-year NFL veteran, spending his whole career with Buffalo.
The Bills are trailing the Rams, 13-12, in the fourth quarter at Ralph Wilson Stadium. The game is being televised on Fox.