Upset Watch appears every Thursday 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), along with home-field advantage and injury data. Each week, we highlight the most likely upset on a game with a line over three points, plus an additional game where a significant underdog has a strong chance to cover.
The big trend for Week 15 in the NFL seems to be superior teams favored on the road. Right now, seven different playoff contenders are favored on the road against teams that are essentially out of the playoff hunt. However, you can't write off the effects of home-field advantage, which is why these games make for a slew of possible upsets in Week 15. Here are the most likely upsets with a three-point spread or greater:
• Minnesota (+4.5) vs. Philadelphia
The game we're choosing for Upset Watch features a team coming off a big, emotional win, on the road to take on one of the league's most underrated squads. It also features two young quarterbacks trying to read two very strong secondaries so they can find the right targets in their two flawed receiver corps.
Upset Watch: Tampa Bay (+5.5) vs. San Francisco
The issue here is not that a trip to Tampa Bay qualifies as some sort of "letdown game" for San Francisco after its big home win against Seattle. Instead, the issue is that Tampa Bay is much better than most people realize. In fact, the Bucs have been better than their record all year long.
After eight games, the Bucs had the best DVOA rating of any 0-8 team in our database, going back to 1989. They ranked 23rd in the NFL, despite not having a win. Now, five weeks later, the Bucs have moved up to 13th in our ratings. The difference between the Bucs and the 49ers (who rank eighth) is about the size of what we usually consider home-field advantage, meaning this game is really a toss-up.
The improvement for the Bucs in their recent 4-1 streak has been entirely on defense. The offense ranked 21st in DVOA through Week 9 and ranks 24th for Weeks 10 through 14, actually dropping slightly. But the defense has improved from minus-3.7 percent DVOA through Week 9 (12th in the NFL) to minus-23.3 percent over the past five weeks (second, with only Seattle performing better).
A big reason for the improvement is that Darrelle Revis is healthier and is now being used in the role he played in New York: covering the other team's best receiver man-to-man. That's brought a dramatic improvement in Tampa Bay's defense against the opposition's top receiver, which in turn has improved the Bucs' pass defense overall. In Weeks 1 through 7, Tampa Bay allowed 9.5 yards per pass to the opponent's top receiver, with an 80 percent catch rate and 71 yards per game. Since Week 8, the first of two games where Revis took on Steve Smith one-on-one, Tampa Bay has allowed 6.5 yards per pass to the No. 1 receiver, with a 53 percent catch rate and 51 yards per game. (This includes the Week 12 game in which Revis was injured halfway through and rookie Johnthan Banks had to cover Calvin Johnson in the second half.)