49ers Christian McCaffrey has had Achilles tendonitis for four weeks or more

Losing a star player would be any team’s Achilles heel, so to speak. Now it appears the recently revealed diagnosis of Achilles tendonitis will keep San Francisco 49ers star Christian McCaffrey out longer than initially expected during the preseason. What was ruled a calf injury in early August had kept the reigning NFL Offensive Player of the Year out of all 49ers’ preseason games. But after McCaffrey was surprisingly retained from the 49ers’ Week 1 regular season game against the New York Jets, Head coach Kyle Shanahan revealed on Tuesday that McCaffrey also had Achilles tendonitis.

That put McCaffrey on injured reserve, causing him to miss the 49ers’ Week 2 game with the Minnesota Vikings. This means that he must serve at least 4 weeks. But it could be longer, as the NFL Network’s Ian Rapoport reported:

Yes, having Achilles tendonitis is no fun. In fact, no tendonitis is fun. Because the suffix ‘-itis’ means inflammation of whatever the ‘-itis’ is attached to, tendonitis is an inflammation of a tendon. A tendon is a tissue that connects muscles to bones.

And don’t sweat it, your Achilles tendon is pretty important. If someone showed you the phrase “The largest tendon in your body” on Jeopardy, your response would have to be, “What is the Achilles tendon?” Your Achilles tendon specifically connects your calf muscle to your heel bone. You shouldn’t have more than two Achilles tendons, one in each leg, assuming you’re not a caterpillar.

You actually use your Achilles tendon every time you extend your foot in any way, including lifting your heel to walk, run, jump or step upstairs. This happens when your calf muscles contract and pull on the tendon and therefore your heel.

Overuse or too much stress on this tendon can lead to Achilles tendonitis. This also includes too much running and jumping, two things that football players do a lot. Such tendonitis can develop when your calf muscles are too tight and pull too hard on the tendon.

The most common symptoms of Achilles tendonitis are pain, tenderness, or stiffness in the back of your lower leg, around where the Achilles tendon is located. You can then see why this can be a little difficult to distinguish from calf tightness or calf strain.

Doctors may be able to diagnose Achilles tendonitis through a physical examination. They will press on your Achilles tendon to see if there is pain there. They may also have you stretch your feet and see if that causes pain. Imaging such as ultrasound or magnetic resonance imaging can help figure out what’s going on there.

The cornerstone of treatment is RICE. No, not the stuff you eat with sushi, but rest, ice, compression and altitude. Anti-inflammatory medications such as ibuprofen can help reduce inflammation. You may also receive physical therapy, which consists of stretching and strengthening exercises for the Achilles tendon and its supporting structures. Orthopedic devices that elevate your heel can also help relieve tension on your tendons.

If you have Achilles tendonitis, you do not want to continue to put strain on your Achilles tendon for two reasons. One: it hurts. The other is that continued use can further damage the tendon, leading to its tearing or rupture. This may require surgery. After all, if you can’t straighten your foot, you can’t really walk.

McCaffrey’s replacement at running back is Georgia grad Jordan Mason, who has done a pretty good job so far. The second-string RB gained 147 yards and scored one touchdown against the Jets and added 100 yards and another touchdown in Sunday’s loss to the Vikings. Mason will have to continue to build on more rushing performances like this, as McCaffrey will be out at least until San Francisco’s Oct. 10 showdown against the Seattle Seahawks. In other words, Mason will have to do what he can to ensure the running game doesn’t become the 49ers’ Achilles heel.