According to CSN Bay Area, the 49ers "backed off" Michael Crabtree's (Achilles) participation a week ago. Crabtree is going to be activated to the 53-man roster before Tuesday's deadline, but that doesn't mean he's going to immediately start playing in games. The Niners want him to continue rehabbing in a controlled environment. Obviously, an NFL game is not exactly controlled. In an absolute best-case scenario, Crabtree will play limited snaps in Week 13 and then ramp up from there.