Mack (shoulder) did not practice Thursday, the Colts' official site reports.
Mack was a limited participant at Wednesday's practice, so the downgrade Thursday is notable. We'll revisit his status Friday, but so far the fourth-rounder's fantasy results have been spotty, as Mack has turned 16 carries over two games into 21 yards and a TD. He's also caught two passes for 32 yards.