The Panthers offensive line is taking some serious hits. Right tackle Daryl Williams is out indefinitely with a dislocated patella and torn ligament in his knee. Fellow tackle Amini Silatolu is also out with a torn meniscus. 

Now, Matt Kalil, the Panthers' star left tackle, is out after undergoing arthroscopic knee surgery. 

The good news is that Kalil is only out on a week-to-week basis, according to the head athletic trainer Ryan Vermillion. However, the ​Panthers are not sure if he'll be back and healthy when the season starts in 19 days. 

With Kalil out, it looks like Taylor Moton could be taking his spot.

This could be a blessing in disguise for the Panthers, who will be forced to try out other players at left tackle and get some other looks at what they have. Kalil hasn't been playing well recently and his expensive salary makes him a liability on the financial side of things too.

But perhaps Kalil's knee has contributed to his declining performance on the field. This surgery could give him a new start and have him playing like a Pro Bowler again.