Mack was pulled from Sunday's game against Miami in the fourth quarter to be evaluated for a concussion, Zak Keefer of The Indianapolis Star reports.
Mack was removed after he took a big hit on a 1-yard loss, leaving Nyheim Hines to handle most of the backfield snaps during a game-tying drive. Mack gained 85 yards on 15 carries and 11 yards on two catches prior to his early exit. He won't be able to return if tests determine he did in fact suffer a concussion.