Without Christian McCaffrey, Jordan Mason was a revelation. He was one of the best running backs in the NFL.

Can the San Francisco 49ers get a similar performance from their third running back on the depth chart? They had to puzzle for a while on Thursday evening.

Mason got off to a good start on Thursday night when he was tackled in a game against the Seattle Seahawks and immediately grabbed his shoulder. He lay there for a while while the trainers looked after him. Mason went back to the locker room and the 49ers said it was questionable whether he would return because of a shoulder injury.

The good news was that Mason returned in the second half, although after just one carry he went to the sideline and moved his injured arm to free himself. Isaac Guerendo came in when Mason went out, and Patrick Taylor Jr. came in on the 49ers' first drive of the second half when Guerendo needed a break. Mason didn't return for the rest of that drive, having completed just one play. Mason did not return for the remainder of the third quarter.

Mason's injury was concerning for the 49ers as they were already missing McCaffrey. Not many teams have a rock-solid third running back option on the roster, although the 49ers' scheme seems to make everyone better. Rookie Guerendo is behind Mason on the depth chart. He's an athletic fourth-round pick but had just 41 career yards before Thursday. Taylor is behind Guerendo. Before Thursday, he hadn't had a carry all season. Deebo Samuel Sr. also grabs a tailback, but the 49ers wouldn't want to turn him into a permanent tailback.

The 49ers may have missed McCaffrey in some ways, but Mason had replaced most of his production. After five weeks, he was second in the NFL in rushing yards, behind only Derrick Henry. Mason had 536 yards, more than 100 yards more than any other defender except Henry.

McCaffrey missed every game this season with a calf/Achilles tendon injury. He is expected to return at some point this season. The 49ers are hoping Mason's injury won't be a problem before McCaffrey can return.