49ers' emerging rookie could be in for larger role after NFL insider reveals details of Jordan Mason's injury

In keeping with the theme of the season, the San Francisco 49ers' win over the Seattle Seahawks came with some injury worries, the foremost concerning NFL rushing leader Jordan Mason.

Mason suffered a shoulder injury in the 49ers' 36-24 victory at Lumen Field and, though he attempted to play through it, he sat out all but one snap of the second half as San Francisco held off a fightback from Seattle to improve to 3-3. Mason finished the game with 73 yards, and now has a league-high 609 on the ground.

Head coach Kyle Shanahan will provide an update on Mason and his likelihood of playing in the Week 7 Super Bowl rematch with the Kansas City Chiefs in his Friday conference call.

But the nature of the injury is now known after a report from ESPN's Adam Schefter.

Per Schefter, Mason is believed to have suffered a sprained AC joint. That is not a serious injury, but he is due to undergo further testing to determine the length of any potential absence.

With Christian McCaffrey still on the sideline with Achilles tendinitis. Mason's injury will likely mean a larger role for rookie fourth-round pick Isaac Guerendo, who essentially iced the game against the Seahawks with a 76-yard run on the 49ers' final series, showcasing the game-breaking speed that led San Francisco to trade up for the former Louisville and Wisconsin back.

Patrick Taylor Jr. will be expected to share some of the workload with Guerendo against the Chiefs if Mason cannot play in that game. Former Tampa Bay Buccaneers running back Ke'Shawn Vaughn could be in the mix for elevation from the practice squad should Mason be ruled out of Week 7.

The 49ers will obviously hope Mason is able to avoid such a scenario with the extra rest their mini bye provides. However, Guerendo's encouraging primetime effort should give the 49ers confidence they have the talent in the backfield to continue to excel even without the NFL's leading rusher.

Related: Kyle Shanahan says what everyone is thinking about officiating error that nearly cost the 49ers Week 6 win