Mason suffered sprained AC joint in 49ers-Seahawks game, is day to day originally appeared on NBC Sports Bay Area

Another star 49ers player suffered an untimely injury.

Running back Jordan Mason, who left Thursday night's road win over the Seattle Seahawks in the second quarter before briefly returning to the field, was believed to have suffered a sprained AC joint, ESPN's Adam Schefter first reported Friday, citing sources, and 49ers coach Kyle Shanahan later confirmed the injury.

Mason injured his shoulder on a second-and-3 play from the 49ers' 13-yard line with 9:38 remaining in the second quarter. The third-year pro walked off the field with trainers and eventually into the 49ers' locker room, but he came back out after halftime and played one snap, an 8-yard run, before watching the remainder of the game from the sideline.

49ers coach Kyle Shanahan told reporters after the game that Mason was available in the second half "in case of emergency," which appeared to be a positive sign that the injury, as Schefter reported, wasn't serious.

Shanahan said Friday that Mason would be "day to day" and classified it as "good news," though he wouldn't guarantee the running back will play in Week 7 against the Kansas City Chiefs.

"Jordan's as tough as anybody," Shanahan said. "I'm sure if he has a chance to play, he will. But we’ve got to just see how the shoulder responds. We're only a day out."

Mason and the 49ers certainly will benefit from the extended time off before that Super Bowl rematch at Levi's Stadium.

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