The San Francisco 49ers went all in this season when they traded for former All-Pro running back Christian McCaffrey. The move created some depth at the running back position, so they traded Jeff Wilson Jr. to the Miami Dolphins, knowing that Elijah Mitchell would be back from injured reserve.

Well, Mitchell hurt his knee again and is now on season-ending IR. The depth is suddenly quite thin and could get even worse. McCaffrey suffered a minor knee injury in the win over the New Orleans Saints last week. 49ers coach Kyle Shanahan said that McCaffrey is dealing with “knee irritation” and will not practice Wednesday, according to Pro Football Focus' Ari Meirov.

The 49ers offense is yet to take the expected leap when they traded for the Pro Bowl tailback. They scored just 13 points last week and struggled for much of the game against the Arizona Cardinals the week prior.

If Christian McCaffrey were to miss Sunday's game against the Dolphins, a combination of Jordan Mason and Tyrion Davis-Price would split work in the backfield. That's a far cry from Mitchell and Wilson Jr. as backups. McCaffrey isn't the only skill position player banged up. Wide receiver Deebo Samuel is dealing with a quad injury and was limited in practice Wednesday.

However, San Francisco's defense is nearly at full strength. Only Arik Armstead is still on the injury report among the starters. The defensive line might feast this week as Miami will be without their All-Pro left tackle, Terron Armstead.

The 49ers lead the NFC West by one game over the Seattle Seahawks.