Jordan Mason, running back for the San Francisco 49ers, is dealing with a shoulder injury that has caused him to be questionable for a recent game against the Cowboys. He had previously played through an AC joint sprain but aggravated the injury during the game. If he cannot return, Isaac Guerendo will take over the backfield duties. Mason was cleared to play in Week 7 after recovering from the injury, indicating his importance to the team's running game.

• Jordan Mason's shoulder injury is a concern for the 49ers' backfield.
• Isaac Guerendo is poised to step up if Mason cannot return.