With Christian McCaffrey out, Jordan Mason was a revelation. He has been one of the NFL’s best running backs.

Can the San Francisco 49ers get similar production out of their third running back on the depth chart? They might have to find out.

Mason was off to a good start on Thursday night when he was tackled and immediately grabbed at his shoulder area. He stayed down for a while while athletic trainers tended to him.

Not many teams have a rock solid third running back option on the roster, though the 49ers’ scheme seems to make everyone better. Rookie Isaac Guerendo is behind Mason on the depth chart. He’s an athletic fourth round pick but had just 41 career yards before Thursday. Patrick Taylor Jr. is behind Guerendo. He hadn’t had a carry all season before Thursday. Deebo Samuel Sr. also takes snaps at tailback, but the 49ers wouldn’t want to turn him into a full time tailback.

The 49ers had perhaps missed McCaffrey in a few ways, but Mason had replaced most of his production. He was second in the NFL in rushing yards to only Derrick Henry after five weeks. Mason had 536 yards, more than 100 yards more than any back other than Henry.

McCaffrey has been out every game this season due to a calf/Achilles injury. He’s supposed to return at some point this season. If Mason’s injury is serious, there will be more urgency to get McCaffrey back.