Harris injured his hamstring during Monday's game at Buffalo.
Harris made an early exit just ahead of halftime after he appeared to come up gimpy at the end of a carry. While he's officially deemed questionable to return, he jogged back to the sideline a few minutes after the Pats made this announcement. If Harris doesn't retake the field, though, Rhamondre Stevenson and Brandon Bolden will man New England's backfield the rest of the way.