49ers head coach Kyle Shanahan told reporters Monday that McCaffrey suffered a posterior cruciate ligament (PCL) injury during Sunday's 35-10 loss to the Buffalo Bills, and will be placed on injured reserve as result. McCaffrey's recovery is expected to be six weeks, meaning that the rest of his season is in jeopardy.

The San Francisco 49ers placed running back Christian McCaffrey on injured reserve Tuesday a day after coach Kyle Shanahan indicated that both he and fellow running back Jordan Mason would go on IR after suffering injuries in the team’s Week 13 loss to the Buffalo Bills.

San Francisco 49ers running back Christian McCaffrey is feared to have suffered a season-ending PCL injury vs. the Buffalo Bills.

San Francisco running back Christian McCaffrey suffered a knee injury that coach Kyle Shanahan described as “potentially” season-ending in the 49ers’ 35-10 loss to the Buffalo Bills on Sunday night.

Star running back Christian McCaffrey will miss the remainder of the regular season with a PCL injury sustained in the San Francisco 49ers' 35-10 loss to the Buffalo Bills on Sunday night.

Among the NFL players who suffered injuries in Week 13, Baker Mayfield entered that unwanted mix. And Taysom Hill took a bad injury. But leading the high-profile way on the injury list, Christian McCaffrey and Trevor Lawrence both failed to finish their respective contests.