Mack (hamstring) isn't practicing Wednesday, Zak Keefer of The Indianapolis Star reports.

Mack hasn't practiced since suffering a hamstring strain in the first week of the preseason. He'll likely be held out of Saturday's exhibition against San Francisco, and the Colts presumably wouldn't play him in the preseason finale even if he were healthy enough to suit up. Mack is still the favorite for the Week 1 starting job and still has time to get ready for the opener, but it isn't a great sign that he's missing out on so many practice reps after sitting out the entire offseason program while recovering from shoulder surgery. With Nyheim Hines struggling will ball protection and Robert Turbin suspended for the first four weeks of the season, Indianapolis may have to lean on Jordan Wilkins and Christine Michael if Mack doesn't progress as expected over the next two and a half weeks.