49ers center Eric Heitmann will miss six to eight weeks of action after breaking his left leg on Monday. David Baas, Tony Wragge and Cody Wallace will compete for playing time with Heitmann out. Baas played with the first team immediately following the injury. "The biggest thing about playing center is that the guys have to believe in you," Baas said. "You have to make those calls quick and precise. Heitmann does an awesome job at that, and I'm trying to get to his level."