Buffalo Bills running back Fred Jackson suffered a right knee injury during Sunday's 48-28 loss to the New York Jets.
Jackson, who missed most of last season because of a broken right leg, went down with 11:07 left in the first half when he was hit hard by LaRon Landry.
Trainers worked on Jackson's right knee for several minutes on the bench before taking him to the locker room.
The initial diagnosis is a sprained lateral collateral ligament. He will have an MRI performed Monday.
Some fantasy football owners are scared off by the injury, as Jackson has been dropped by 648 teams in Yahoo Sports fantasy leagues.
The Associated Press contributed to this report.
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