Mostert (knee) won't participate in Wednesday's practice, Nick Wagoner of ESPN.com reports.
After failing to practice at any point last week while managing the sprained MCL, Mostert wasn't able to take a notable step forward in the 49ers' first session of Week 4. If Mostert isn't able to play Sunday against the Eagles, the 49ers will once again have to deploy a backfield committee consisting of Jerick McKinnon, Jeff Wilson and JaMycal Hasty.