Williams watches. (Dave Einsel / AP)

Williams, who was hurt sacking Jason Campbell, is expected to undergo an MRI to determine the extent of the injury, but NBC’s Peter King reports that there may be a tear in the muscle.

Williams watched the second half of the game in street clothes, with rookie Brooks Reed replacing him.

The Texans lost another star, running back Arian Foster, last week with a hamstring injury. He’s out two-to-three weeks.