Mitchell (concussion/knee) was estimated as a non-participant on Monday's injury report, Cam Inman of The San Jose Mercury News reports.
Mitchell hasn't practiced since being diagnosed with a concussion following a Week 12 loss in Seattle. He's also been bothered by knee irritation at the same time, but coach Kyle Shanahan said Monday that he's "holding out hope" that Mitchell will return for Thursday's contest at Tennessee, per David Lombardi of The Athletic. Mitchell will have two more chances to make his presence felt on the practice field before the 49ers potentially make a determination on his status for Week 15.