Why to watch
It's a potential Super Bowl showdown, and a rare Monday night game recently that features two contending teams. This is a battle of two of the NFL's best defenses, with some Ben Roethlisberger drama as the cherry on top. Will he play, or will he sit? Will he walk, or will he limp?
Inside story
This is a rare test for the 49ers' revamped elite secondary, with the Steelers getting young speedsters Antonio Brown and Emmanuel Sanders more involved each week. The 49ers' running game has quietly slowed, and Pittsburgh restored its roar stopping the run as the season has gone on. It will be interesting to watch how Alex Smith fares against the zone blitz.