Christian McCaffrey followed a worrisome slide with a troubling exit to the locker room on a snowy night in Buffalo.
McCaffrey slid down on a run without contact and was ruled out of the San Francisco 49ers' 35-10 loss on Sunday night to the Bills with a knee injury that could potentially end his season, head coach Kyle Shanahan told reporters after the game.
Shanahan said that McCaffrey's injury was to the PCL (posterior cruciate ligament) in his knee.
McCaffrey, playing in his fourth game of the season after missing the first eight with Achilles and calf injuries, took a pitch right and after a step or two slid to the ground. He popped up and jogged to the sideline, briefly visiting the medical tent before moving on to the locker room.
In a season during which San Francisco has been besieged by injuries, McCaffrey's was the biggest and first to plague the 49ers. His new issue creates a massive cause for concern.
McCaffrey missed training camp and the preseason as a precaution for what was initially described as a calf issue. But McCaffrey's injury lingered and he was placed on injured reserve after Week 1.
McCaffrey did not look like his normal self in his return from IR, averaging just 49.7 rushing yards per game in his first three contests.
After his 5-yard loss on his final attempt Sunday night, he had seven carries for 53 yards with a 19-yard gain providing a flash of the CMC of old before the injury reared its head.