The NFL playoffs are set, giving us a chance to look over the field and separate the pretenders from the contenders.



Last year's defending champions, the top-seeded New England Patriots, will try to win back-to-back titles while enjoying home-field advantage throughout the playoffs, ensuring that any Super Bowl run from the conference runs through Gillette Stadium.



They appear to be a worthy favorite — the Westgate Las Vegas SuperBook has them as a 2-to-1 odds — after scoring a league-high 2.6 points per drive behind an MVP-caliber season from quarterback Tom Brady, the third-most valuable passer in 2017 per ESPN's Total Quarterback Rating.



However, there is at least one reason to doubt their chances of winning coach Bill Belichick a sixth Super Bowl ring with the franchise: The Patriots have net passer rating differential of 13.1, the 10th highest in the league this season.



Dubbed the "Mother of All Stats" during the 2012 Pro Football Researchers Association biennial meeting hosted by NFL Films, net passer rating has been a good litmus test for Super Bowl caliber teams. Since 2002, 22 of the past 30 Super Bowl participants had a passer rating differential among the top five best in the league, including 10 of the past 15 winners. The outliers among the eventual Super Bowl winners include the 2005 Pittsburgh Steelers (7th), 2007 New York Giants (24th), 2011 Giants (12th), 2012 Baltimore Ravens (12th) and the 2015 Denver Broncos (18th).



By this metric, the Minnesota Vikings look every bit a Super Bowl contender. Quarterback Case Keenum produced a passer rating of 98.3 in 14 starts (the team's overall passer rating was 99.1) and played well enough to finish the regular season ranked No. 2 in QBR. The defense, led by defensive end Everson Griffen, set a career high in sacks (13) and was ranked as the 10th best edge rusher per the game charters at Pro Football Focus. Minnesota's secondary was also rated as the fourth-best in pass coverage, resulting in the third-lowest passer rating against (73.0) in 2017. The result: a league-leading net passer rating differential of 26.1.



The New Orleans Saints were not far behind. Quarterback Drew Brees led the league in completion percentage (72 percent) and finished the year with a 103.9 passer rating. Their defense, meanwhile, improved significantly from the 2016 campaign, allowing just a 79.0 passer rating against in 2017, giving them the league's second-best net passer rating differential. The Los Angeles Rams, Kansas City Chiefs and Philadelphia Eagles round out the top five.



Aside from the Patriots, the Pittsburgh Steelers are also noticeably absent from the leader board. Quarterback Ben Roethlisberger posted a 93.4 passer rating and the defense had an above-average pass defense at 81.8 against, giving them a net passer rating differential of plus-12.3, the 12th best in the NFL this season. But that does fall outside of the top 10, discounting their chances at a championship run.



Two playoff teams, the Tennessee Titans and Carolina Panthers, have negative passer rating differentials, making their title hopes a long shot, at best.