The initial diagnosis for Jackson is a sprained lateral collateral ligament, a league source tells ESPN NFL Insider Adam Schefter. Jackson is scheduled for an MRI on Monday.
Jackson, who went on injured reserve last November with a broken right leg, went down with 11:07 left in the first half Sunday when he ran for 7 yards and was hit hard by LaRon Landry. Jackson went down immediately and stayed down for a few moments while he was checked by trainers before walking on his own to the sideline.
Trainers worked on Jackson's right knee for several minutes on the bench. He walked around on the sideline for a while before finally heading to the locker room, a towel draped over his head, with two trainers accompanying him.
C.J. Spiller replaced him and got the Bills on the scoreboard, zipping past a few missed tackles by Landry and Bart Scott and scooting into the end zone for a career-best 56-yard score. Spiller finished with a career-best 169 yards rushing.
Information from The Associated Press was used in this report.