The 49ers designated Mitchell (knee) to return from IR on Monday, Josh Dubow of The Associated Press reports.
Mitchell sprained his MCL during the season opener and has been on IR since. Jeff Wilson replaced him at first, but the 49ers since have traded Wilson to the Dolphins after acquiring Christian McCaffrey from the Panthers. With the move, Mitchell can practice ahead of Week 10, opening a 21-day window for the running back to be added to the active roster. However, it doesn't sound like Mitchell will remain sidelined for much longer, as Matt Maiocco of NBC Sports Bay Area reported last week that Mitchell has been eyeing a return to action against the Chargers in Week 10. Regardless, when Mitchell eventually is activated, it's possible he'll be limited at first, and even when he's back to full speed, he'll operate as the No. 2 back behind McCaffrey.