Upset Watch appears every Thursday this season for ESPN Insider, as Football Outsiders uses a proprietary formula to forecast the expected point spread of each game based on current DVOA ratings (explained here) and, early in the season, our DVOA projections. Each week, we highlight the most likely upset on a game with a line over three points plus an additional game in which a significant underdog has a strong chance to cover.
Upset Watch: Chicago (+5) at San Francisco
Last year, these were two very similar teams -- at least until Jay Cutler got injured at midseason. Both Chicago and San Francisco had very good defense and special teams, combined with average offense.
This year, things are a bit different. San Francisco is dramatically better on offense but only average on special teams. Chicago's offense is worse than it was during the first half of 2011, but the Bears have one of the best defenses in NFL history.
Yes, I said NFL history. The quality of Chicago's defense in 2012 may actually be underplayed in the media. There has been a lot of talk about their interception and fumble return touchdowns and not enough about just how good the Bears have been at preventing yardage and first downs. Football Outsiders DVOA ratings go back to 1991, and in the past 22 years, only one team put up a better defensive rating than the 2012 Bears through the first 10 weeks of the season: the 2002 Tampa Bay Buccaneers.