Mack (shoulder) returned to practice Tuesday, the Indianapolis Star reports.
Mack missed several practices last week and the Colts' first preseason game, though the shoulder injury isn't thought to be serious. Head coach Chuck Pagano has raved about his performance in training camp, but Mack will likely need to showcase his talents in a preseason game if he's going to climb the depth chart early in the season. He's currently battling Robert Turbin and Josh Ferguson for touches in the backfield behind Frank Gore.