Mitchell (concussion/knee) wasn't spotted at the media-access portion of Friday's practice, Matt Maiocco of NBC Sports Bay Area reports.
Mitchell hasn't made any notable progress through the concussion protocol this week, which has coincided with him dealing with "knee irritation" as well. The pair of injuries may conspire to keep him sidelined for a fourth time this season, something that could be confirmed as early as the release of Friday's practice report. In the event he does sit out Sunday in Cincinnati, Mitchell will hand off backfield duties to some combo of Jeff Wilson and JaMycal Hasty.