The Panthers have not been able to run because of the o-line. Teams are figuring out how to attack the running game, and why Cam is running for his life.
The o-line is a weak link to this team mostly due to injury. The Panthers lost their starting LG (Amini the #2 draft pick last year) and were fortunate to sign Wharton. They lost their starting RG (Williams), and the backup RG Byers, and then the backup to the backup (Scott) and now have a converted D-Lineman as the starter (Chandler). Not too mention they also lost a key backup in Campbell, as well as their Kugbilla.
Bell is an average at best LT, but when you have that much injury at RG there is definitely going to be transition, inconsistent play, and lack of execution especially on the right side of the o-line. Gross, Wharton, and Kalil are holding it together, but they can't do it all. That is why Hartsock & Brockel are valuable.....they help hide the o-line's problems. Hopefully Harsock is back next game.