Mitchell, who won't practice Wednesday due to a concussion and knee irritation, worked on a side field with a member of the 49ers' training staff, Cam Inman of The San Jose Mercury News reports.
Mitchell wasn't spotted on the field at all last week, so this is a somewhat positive development, even if it doesn't translate to practice reps. Still, he has multiple checkpoints to clear as he works his way through the five-step concussion protocol, making it far from certain that he'll put an end to a one-game absence this weekend against the Falcons. While Mitchell was sidelined this past Sunday against the Bengals, Jeff Wilson served as the primary runner for San Francisco, finishing with 13 carries for 56 yards, while receiver Deebo Samuel matched his season high with eight carries to go with one reception.