Even if Roethlisberger plays, he might not be at full strength.
The Steelers found out Tuesday they'll be without one of their top defenders when the NFL levied a one-game suspension against linebacker James Harrison for the hit Harrison put on Cleveland Browns quarterback Colt McCoy.
The 49ers' pass protection has been shaky in recent weeks. The team lost left tackle Joe Staley to a concussion against Arizona in Week 14.
Harrison lines up at right outside linebacker about 80 percent of the time. Removing him from the lineup spares Staley or backup Alex Boone from matching up with one of the more feared defensive players in the league.
Harrison has three-sack games against Cincinnati and Baltimore this season. He plans to appeal his suspension, but a reversal appears unlikely, based on precedent.