Christian McCaffrey going down under his own power is 49ers latest nightmare [UPDATED]

It doesn't matter if you're a San Francisco 49ers diehard or a neutral, every football fan has got to appreciate Christian McCaffrey with the ball in his hands. We haven't seen enough of that this season because of injury. Sadly, the delicious taste of it we got on Sunday Night Football didn't last.

In the second quarter, McCaffrey took a handoff to the right but he slid down into the snow before any defenders got near him. Clearly injured, he gingerly trotted to the blue medical tent before making his way to the locker room.

McCaffrey has been dealing with tendonitis in both his left and right calf this year. Running on a slurry of snow and frozen turf can't have been good for that injury. But the 49ers didn't call it a calf injury. That's not good news.

Christian McCaffrey injury update: 49ers RB

UPDATE: Head coach Kyle Shanahan revealed McCaffrey likely suffered a PCL injury. The posterior cruciate ligament crosses beneath the ACL (anterior) to connect the femur to the tibia. The good news is the PCL is more hardy than the ACL. Packers cornerback Jaire Alexander played through a torn PCL earlier this season.

That doesn't mean McCaffrey should be expected back soon. Shanahan couldn't say if the running back would play again this year.

Given his Achilles and calf injuries, McCaffrey may be best off sitting out and getting fully right. The 49ers are 5-7 after all. It could be in the team's best interest to hold him out.

The team announced that McCaffrey is questionable with a knee injury.

Aggravating his calf problems would be one thing. Sustaining a non-contact knee injury is a whole other concern.

As if that wasn't problem enough, linebacker Fred Warner also made his way to the locker room with cramps. The 49ers termed him questionable to return as well.

Before going down, McCaffrey had just done this:

That's vintage McCaffrey, looking every bit the MVP level player he's been when healthy in his career. It's a damn shame he's not still out there.

We'll keep an eye on more updates on McCaffrey's status as they come in.