Mitchell (shoulder), who is listed as questionable for Sunday's game against the Seahawks, isn't expected to play in the contest, Adam Schefter of ESPN reports.
Official confirmation of the running back's Week 4 status will arrive once inactives are posted in advance of Sunday's 4:05 p.m. ET kickoff. If Mitchell is indeed unavailable, Trey Sermon would once again be in line for an expanded role in the 49ers' backfield.