Mitchell is not expected to play in Saturday's preseason opener against the Chiefs, according to Eric Branch of the San Francisco Chronicle.
Mitchell was able to take part in the 49ers' last practice session prior to Saturday's contest, but he was listed among the players on the "Anticipated Will Not Play" list cited in the report. Regardless of the reason for Saturday's absence, he should have a chance to see his first action as a professional in the 49ers' second exhibition contest next Sunday against the Chargers.