Christian McCaffrey’s backup lands on IR as 49ers lose 2 running backs in roller-coaster season

The Buffalo Bills hammered the San Francisco 49ers, 35-10, in a snow-filled rout led by Josh Allen’s 4 TDs. Colin Cowherd explains why he feels like this is the year for the Bills to win the Super Bowl.

Just as the San Francisco 49ers confirmed Christian McCaffrey suffered a season-ending PCL injury in the loss to the Buffalo Bills on Sunday night, his backup is also heading to injured reserve. 

Jordan Mason, who filled in admirably for McCaffrey as he dealt with Achilles tendinitis in both his ankles at the start of the season, will miss at least the next four games due to a high-ankle sprain also suffered in the blowout loss to the Bills. 

The 49ers have no choice but to turn to rookie Isaac Guerendo to be their lead running back for what could possibly be the rest of the season with just five games remaining.

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San Francisco 49ers running back Jordan Mason is shown during the first half against the Buffalo Bills on Dec. 1, 2024. (IMAGN)

For McCaffrey, 49ers head coach Kyle Shanahan noted that his star could "potentially" be out for the remainder of the season. 

"I think PCL is usually a couple weeks, but I’m not exactly sure yet," Shanahan said prior to learning that it’s six weeks for him to heal with not that many games remaining on the schedule. 

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At 5-7 after losing three straight, the 49ers are grasping at straws hoping they can go on a run to end the year and get back into the playoffs.

But they currently sit in last place in the NFC West, though the division-leading Seattle Seahawks are only 7-5.

San Francisco 49ers running back Christian McCaffrey runs with the ball