49ers get a brutal Christian McCaffrey injury update ahead of Week 2

Just a couple of days ago, the San Francisco 49ers opened the season with a big win over the New York Jets on Monday Night Football.

Prior to the game, though, the team got a tough bit of news as it was announced Christian McCaffrey was not going to play. The news also created a little bit of drama of its own, but that's a different story.

In the end, Jordan Mason got the call and performed well. The 49ers didn't just survive without McCaffrey, they didn't miss a beat. Mason played lights-out.

Because the McCaffrey news caught many by surprise and seemed more precautionary than anything, fans might have figured he'd be good to go for Week 2 against the Vikings.

Not so fast, though, says insider Ian Rapoport.

"The 49ers all thought that Christian McCaffrey was going to shake off a little tightness that he felt late in the week of practice, be able to work out and be able to play Monday night against the Jets," Rapoport said Wednesday morning.

"We talked a lot during the course of the preseason of Christian McCaffrey's calf injury ... it is more than that. It is also Achilles tendinitis, which can really be troublesome ... that's actually the injury that's giving Christian McCaffrey more trouble right now."

If McCaffrey can't go against Minnesota in Week 2, it will be Mason getting the start once again.

What is Achilles tendinitis and how long could Christian McCaffrey realistically be out?

In simple terms, what McCaffrey is dealing with is the overuse of the Achilles tendon -- the tendon which connects the calf muscle to the heel. Symptoms include swelling, stiffness and tenderness at first, according to the Mayo Clinic.

Most cases can be treated with at-home care, so this shouldn't be too serious of an injury for McCaffrey. There have been more serious cases which have led to ruptures of the tendon, itself, requiring surgery.

For the moment, it doesn't seem as though McCaffrey's injury is deemed to be serious. The 49ers will, of course, take things cautiously with their star running back. It is a long season, and Mason proved he is more than capable of stepping in and performing.

If McCaffrey misses a couple of games to start the year, so be it. His injury history isn't something that should be taken lightly, therefore ensuring he comes back at 100 percent should be priority.