49ers head coach Jim Harbaugh met with the media today and announced that the team would promote rookie outside linebacker Cam Johnson from the practice squad to the team's 53-man roster. The 49ers have been at a 52-man roster since last week.
The decision to promote Johnson is likely connected to Clark Haggans' absence from practice. The 49ers backup OLB has been dealing with a shoulder issue, and sat out all three practice sessions this week. Given his role as the primary backup, this could very well mean Johnson might be active on Sunday. Haggans gets some special teams time, along with a few OLB snaps, which would seem to benefit the activation of Johnson.
The 49ers have also listed Justin Smith as questionable for Sunday. If he is unable to go, the general belief is that Ian Williams will be active for the first time this year. Ricky Jean-Francois will be starting at defensive end in place of Smith. RJF is normally the primary backup at all three defensive end positions, so this means Williams and Tukuafu will split backup duties. It is also worth noting that Isaac Sopoaga can play defensive end, but with Williams and Tukuafu available, I would imagine Ice would stick with his nose tackle role.