San Francisco 49ers star running back Christian McCaffrey’s season is in jeopardy after he suffered a suspected posterior cruciate ligament injury in Sunday’s 35-10 loss to the Buffalo Bills in Orchard Park, NY

“I think it’s potentially the end of the season,” 49ers head coach Kyle Shanahan said after the game. “I think PCL usually lasts a few weeks, but I’m not sure yet.”

McCaffrey will undergo further testing on Monday to determine the severity of the injury.

He appeared to have suffered the injury after being brought down by Bills safety Taylor Rapp at the end of an 18-yard gain with 12:58 left in the second quarter on Sunday. McCaffrey briefly left the play before returning to make a pitch to right, but then decided to slide onto the field without making contact, resulting in a 5-yard loss.

The 49ers originally listed McCaffrey as questionable to return shortly after he left the field for further evaluation. However, Shanahan later told NBC that the 28-year-old was done with the game.

“It was frustrating,” Shanahan said after the game. “He had a great week of training and I could feel his urgency and stuff and thought he came out great, looked really good and it looked like he had just done his little thing there. … It was painful for him and hard for us.” Team doesn’t have him.

The 49ers (5-7) have lost three straight games heading into next Sunday’s game against the Chicago Bears (4-8) in Santa Clara, California. San Francisco is two games behind the NFC West-leading Seattle Seahawks (7-5). ), with five games still on the schedule.

Seattle and San Francisco split their season series.

The 49ers are expected to once again rely on Jordan Mason, who leads the team in carries (153) and rushing yards (789) as well as three touchdowns this season.

McCaffrey had 53 yards on seven carries Sunday night and caught two passes for 14 yards before exiting. He played only his fourth game of the season after missing the first eight games due to Achilles tendonitis in both legs.

McCaffrey was the NFL Offensive Player of the Year last season when he led the league with 2,023 yards from offense: 1,459 rushing yards and 14 touchdowns plus 67 catches for 564 yards and seven scores.

McCaffrey hasn’t scored a touchdown in his four appearances this season. He rushed for 202 yards on 50 carries and caught 15 passes for 146 yards.

–Field level media