Browns coach Mike Pettine said recently that the team is planning to use a committee system at running back this season. We know that free agent acquisition Ben Tate and rookie Terrance West will be part of that mix, but there’s some jockeying going on for the other spots on the depth chart. One of the aspiring runners is Dion Lewis, who broke his leg last summer and missed a season that may have offered him ample playing time once the Browns traded Trent Richardson to the Colts. The Browns have changed coaches and offenses since Lewis was injured, leaving him unsure of how he fits but eager to show that he can thrive in offensive coordinator Kyle Shanahan’s system. “I don’t know,” Lewis said, via the Akron Beacon Journal. “I’m still very excited to get back there and prove that I’m 100 percent recovered from the injury. With new coaches, everybody is learning a new system. So I feel like I’ve learned the system well, and I’m looking forward to getting out there and competing with the rest of the guys.”