Best, the leading rusher and a receiving threat for the 5-1 Lions, did not practice all week. Maurice Morris and Eldra Buckley, who was signed to the 53- man roster Friday, are expected to get carries in Best's absence.
Best has rushed for 390 yards and two touchdowns in six games this season, while catching 27 passes for 287 yards and a score.
Additionally for the Lions, wide receiver Rashied Davis (foot) and safety Vincent Fuller (elbow) are doubtful. Defensive end Willie Young (calf) and cornerback Aaron Berry (groin) are listed as questionable.