Mack (hamstring) is listed as questionable for Sunday's game against the Texans, Andrew Walker of the Colts' official site reports.
A limited practice participant all week, Mack continues to battle a hamstring injury that has lingered since the Colts' preseason opener on Aug. 9. Coach Frank Reich said Friday that Mack is "making progress" in his recovery, but a pregame workout seemingly will be the tipping point for active or inactive status Sunday. In the event he's unavailable again, Nyheim Hines and Jordan Wilkins will split reps out of the backfield.