Mitchell (knee) likely sprained his MCL in Sunday's win over the Saints, but the injury isn't to the same knee as his Week 1 MCL sprain, per coach Kyle Shanahan, Eric Branch of the San Francisco Chronicle reports.
Mitchell sat out Weeks 2-8 due to the first MCL sprain, which suggests he could be facing another multi-week absence, though the 49ers will do more testing before releasing a return timetable. Shanahan believes this injury is less severe than Mitchell's previous MCL sprain, per Matt Maiocco of NBC Sports Bay Area. Christian McCaffrey will lead the 49ers' backfield in Mitchell's absence, with Jordan Mason and possibly fellow rookie Tyrion Davis-Price on hand as well.