Raheem Mostert sustained a mild MCL sprain during Sunday's 31-13 road victory against the Jets, Adam Schefter of ESPN reports.
Backfield mate Tevin Coleman, who also hurt his knee Sunday.
Related players: Jerick McKinnon, Jeff Wilson
Mostert departed the game in the second quarter, but not before accumulating 107 yards from scrimmage on 10 touche. Coleman had 12 yards on 14 carries. Because of those injuries, McKinnon (three rushes for 77 yards and a score) and Wilson (two runs for three yards) rounded out the 49ers' healthy running backs, the story said. Remember, the team signed McKinnon to be the go-to back a couple of years ago before getting hurt, so he could be finally getting his chance if Mostert and Coleman miss time.