San Francisco 49ers star running back Christian McCaffrey has been ruled out of Sunday’s game against the host Minnesota Vikings and could be placed on injured reserve.

McCaffrey is dealing with Achilles and calf injuries that caused him to be a game-day scratch for Monday’s season opener against the New York Jets. The injury hasn’t calmed down this week and San Francisco coach Kyle Shanahan said Thursday was McCaffrey’s “worst day” dealing with the injury.

“(Injured reserve) is something we are considering now,” Shanahan told reporters on Friday. “Yesterday was his worst day. It’s on and off but with him having the worst pain yesterday, it’s something we are going to be discussing in the next 24 hours.”

McCaffrey practiced on a limited basis on Wednesday and Thursday before sitting out Friday’s workout.

A move to the IR would require McCaffrey to miss four games before he returns. If done before the Minnesota game, McCaffrey would be eligible to return Oct. 10 against the Seattle Seahawks.

McCaffrey, a three-time Pro Bowl selection, led the NFL with 1,459 rushing yards last season. He has four 1,000-yard rushing seasons and two 100-catch campaigns in 91 games (84 starts) for the Carolina Panthers (2017-22) and 49ers.

Former undrafted free agent Jordan Mason will again be the main ball carrier against Minnesota. He had a career game with 147 yards on 28 carries against the Jets.

San Francisco listed safety Talanoa Hufanga (knee) as doubtful and linebacker Dee Winters (ankle) as questionable.

–Field Level Media