Mitchell rushed six times for 24 yards in Sunday's 34-10 preseason win over the Raiders.
Mitchell was serviceable in his first appearance as a pro. However, with Raheem Mostert, Trey Sermon, JaMycal Hasty and Wayne Gallman all excelling Sunday, it remains to be seen whether the rookie sixth-rounder has done enough to make the Niners' roster for Week 1's matchup against the Lions.