Head coach Kyle Shanahan said after Sunday's 35-10 loss to the Bills that McCaffrey (knee) suffered a PCL injury in the contest that may be season-ending, Ian Rapoport of NFL Network reports.
Making only his fourth appearance after missing the 49ers' first eight games due to a strained calf and bilateral Achilles tendinitis, McCaffrey injured his right knee while he attempted to plant his feet and move upfield on a pitch, only to slide down and take a five-yard loss. After initially heading to the locker room and being listed as questionable to return, McCaffrey was ruled out for the rest of the night. The star running back will likely undergo further testing Monday to confirm that he's dealing with a PCL injury, and in the likely event that McCaffrey misses time, Jordan Mason and Isaac Guerendo will be relied upon to lead San Francisco's backfield. If McCaffrey doesn't play again in 2024, he'll finish the campaign with 50 carries for 202 yards, 15 catches on 19 targets for 146 yards and zero total touchdowns.