Buffalo Bills running back Fred Jackson has a concussion and will miss Thursday's game against the Miami Dolphins.
Jackson was hurt late in Sunday's 37-31 loss to the New England Patriots.
In seven games this season, Jackson has rushed for 298 yards and three touchdowns. He has also caught 26 passes for 183 yards and one score.
C.J. Spiller will get the majority of the carries in Jackson's absence. The Clemson product has 632 rushing yards and four touchdowns to go along with 28 receptions for 297 yards and a score.