The 49ers expect Mitchell (hamstring) to return in time for Week 1 at Chicago, David Lombardi of The Athletic reports.
Mitchell hasn't practiced since at least Aug. 10 and won't play in any preseason games. His spot atop the depth chart isn't in question, but there is doubt about his ability to stay healthy after he suffered a handful of different injuries last last year, missing six games and then having minor knee surgery in the offseason. Mitchell was healthy for the start of training camp and practiced for about two weeks before the hamstring injury popped up. If he doesn't make it back for the opener, Jeff Wilson would be the favorite to fill in as San Francisco's top running back.