The quest for a Super Bowl ring starts Saturday and as the postseason opens, the New England Patriots are odds-on favorites.

Coach Bill Belichick saw his team win 14 games this season despite quarterback Tom Brady and tight end Rob Gronkowski missing time. But the Pats aren’t perfect.

Their passing game has been exceptional. Brady emerged as an MVP candidate despite missing four games by throwing 28 touchdowns against two interceptions, breaking the NFL’s touchdown-to-interception record set by Nick Foles of the Philadelphia Eagles in 2012 (27-to-2). Brady’s two interceptions were the only ones thrown by the Patriots, beating the previous record, held by the 1990 Kansas City Chiefs, by three.

The running game is another matter. New England managed 3.9 yards per carry this season (league average was 4.2), ranking them 25th in the NFL. The 2011 New York Giants were the last champion to rank lower and three of the last four Super Bowl winners were all above average. The lone outlier? The 2014 Patriots.

But in addition to the low yards per carry, New England was the 18th most-efficient rushing team per Football Outsiders and its offensive line helped convert just 41 percent of runs on third or fourth down, two yards or less to go, into a first down or touchdown, for the fourth-lowest rate in the NFL. Only the Minnesota Vikings, Tampa Bay Buccaneers and Green Bay Packers were worse.

The Patriots also struggle rushing the passer and have to overcome some of the best offensive lines in the league if they are going to appear in their second Super Bowl in three years.

Even with these flaws, the betting markets gives the Patriots the highest chance to win Belichick and Brady their fifth Super Bowl ring (31 percent chance). The rest of the league won’t be as lucky.

If these teams fall short, these will be the most likely causes.

AFC

Kansas City Chiefs

The Chiefs’ offensive line allowed an above-average sack rate after adjusting for down, distance and opponent (6.4 percent compared to a league average 6.1 percent) with right tackle Mitchell Schwartz allowing nine sacks, the most among tackles this season. Overall, Kansas City’s offensive line was responsible for 21 of the team’s 32 sacks allowed during the regular season (running backs, tight ends or quarterback Alex Smith’s own decision-making accounted for the rest).

The trickle-down effect is significant. Smith has a 98.2 passer rating in a clean pocket compared to 65.5 under pressure. His completion percentage also drops from 71.5 to 50.5 percent when facing a pass rush. That’s roughly the difference between facing Kirk Cousins and Ryan Fitzpatrick in 2016.

Pittsburgh Steelers

The Steelers allowed 4.3 yards per carry this season, but were extremely vulnerable once an opposing running back got beyond the line of scrimmage. Pittsburgh surrendered 1.22 second-level yards per carry (yards earned by opposing running backs against a team between 5-10 yards past the line of scrimmage) and 0.90 yards per carry in the open field (more than 10 yards past the line of scrimmage), ranking them No. 20 and No. 27, respectively, in the NFL. Since 2002, the year the NFL went back to an even number of teams (32), only the 2006 Indianapolis Colts managed to win the Super Bowl while being below average (ranked 16 or worse) in both categories.

Houston Texans

Considering the Texans’ big defensive liability, they may have received a big break by getting the Oakland Raiders and their banged-up collection of quarterbacks.

In four of Houston’s seven losses this season, opposing quarterbacks have thrown for multiple touchdowns with one or fewer interceptions. Three of those four losses have come on the road. As the No. 4 seed, the Texans will host a wild-card game against the Raiders, but will have to succeed away from NRG Stadium to have a deep playoff run.

The weak spot those quarterbacks keep picking on? Cornerback Kareem Jackson. Jackson has allowed 1.57 yards per cover snap this season – sixth-most among corners – and a 106.8 passer rating against while in primary coverage.

Oakland Raiders

The Raiders will have to make a championship run without their MVP-caliber starting quarterback, Derek Carr.

Carr required surgery to repair a right fibula broken during the Week 16 victory against the Indianapolis Colts and backup Matt McGloin suffered an injury to his left shoulder in the Raiders’ 24-6 Week 17 loss to the Broncos, forcing Jack Del Rio to turn to rookie Connor Cook in the playoffs.

Cook, Oakland’s fourth-round draft pick out of Michigan State, completed 14 of 21 passes for 150 yards, with one touchdown and one interception in relief of McGloin.

According to ESPN, Carr was worth 20.4 points above an average quarterback. If we subtract those 20 points from their total points scored and also keep the defense unchanged, based on Bill James’ Pythagorean expectation, we would expect the Raiders to win eight games, making them barely a playoff team.

Miami Dolphins

Miami’s offensive line doesn’t protect its quarterback that well (6.3 percent adjusted sack rate, No. 22 in the NFL), and there has been just one Super Bowl champion in the last five years to rank worse in pass protection: the Seattle Seahawks.

The Seahawks, however, had Russell Wilson under center, one of the most mobile passers in the game. The Dolphins will will suit up backup Matt Moore for the playoffs with Ryan Tannehill recovering from ACL and MCL sprains in his left knee. In three regular-season starts in 2016, Moore has seen his completion rate drop from 70.7 to 48.3 percent under pressure.

NFC

Dallas Cowboys

It’s a risky proposition having a rookie quarterback in the playoffs, but Dak Prescott did everything the Cowboys have needed him to do and more during the regular season. He’s completed 67.8 percent of his passes for 3,667 yards and 23 touchdowns and ranks third in ESPN’s QBR rating, behind MVP front-runners Matt Ryan and Brady.

But Prescott’s performance against a top-10 pass defense compared to everyone else is enlightening. He has an 86.9 passer rating against the better pass defenses in the league (6.6 yards per pass, 7-to-3 touchdown-to-interception ratio) but feasts on those outside the top 10 with a 122.1 rating (9.3 yards per pass, 16-to-1 touchdown-to-interception ratio).

Four potential playoff opponents are currently in the top 10: the New York Giants and Seattle Seahawks in the NFC, and the Houston Texans and Kansas City Chiefs in the AFC. And just a reminder that he’s already lost twice to the Giants.

Atlanta Falcons

The Falcons, behind quarterback Matt Ryan, have a high-flying offense that can score a lot of points. The problem is their defense allows a lot of points, too.

Atlanta allows 2.2 points per drive this season, seventh-highest in the NFL, and is especially poor in the red zone. Opponents have scored a league-high 5.9 points per trip inside the 20-yard line. Since the 2007 New York Giants, no eventual Super Bowl champion has ever ranked worse than 15th in red-zone points allowed.

Seattle Seahawks

The Seattle Seahawks allow the fifth-lowest passer rating against (83.4), but because Pro Bowl corner Richard Sherman patrols just one side of the field a majority of the time and star safety Earl Thomas is out for the season, teams can hone in on Jeremy Lane in coverage. And that’s a very bad thing for the Seahawks.

Lane allows 1.32 yards per cover snap for a 123.7 passer rating against. For perspective, Matt Ryan leads the league in passer rating against with 115.5 and the highest rating in NFL history over the course of a season (minimum 200 pass attempts) is by Aaron Rodgers, 122.5 in 2011. When asked to cover the slot receiver, Lane allows a 110.4 rating against. Sherman, meanwhile, allows 0.99 yards per cover snap and a 60.8 rating against.

Seattle held opposing quarterbacks to a 75.6 passer rating in wins this season, but saw that rise to 108.8 in their five losses. The Seahawks also averaged an interception per game in those 10 victories, but just one interception total in five losses. Quarterbacks completed 18 of 21 passes with three touchdowns when targeting Lane in those losses.

Green Bay Packers

The Packers, like the Falcons, struggle defending their red zone (5.36 points allowed per trip, fourth-most in the NFL). Green Bay also struggles in pass coverage – according to the game charters at Pro Football Focus, only the Indianapolis Colts and New Orleans Saints, two non-playoff teams, were worse.

One of Green Bay’s corners, Quinton Rollins, leads the league in yards allowed per cover snap (1.63) and all three of their primary defensive backs – Rollins, Ladarius Gunter and Micah Hyde – allow an above-average passer rating in primary coverage.

This could be a massive problem. Three of the five best passers per ESPN’s Total Quarterback Rating are on playoff teams in the NFC and one other, Brady, resides in the AFC. The Packers’ own quarterback, Aaron Rodgers, is the other passer in the top five. He’ll have his work cut out for him if his defense can’t limit the opposition to field goals instead of touchdowns when they break inside the 20-yard line.

New York Giants

The Giants did a below-average job at controlling the line of scrimmage when they chose to rush the ball. According to Football Outsiders, the team managed just 3.61 adjusted line yards per carry (No. 24 in the NFL), which assigns responsibility to the offensive line after adjusting for down, distance, situation, opponent and the difference in rushing average between shotgun compared to standard formations. You have to go back to the 2011 Giants to find a champion that was worse during the regular season. Three of the last four Super Bowl winners all ranked in the Top 10.

Injuries were part of the problem, but Will Tye led the team’s tight ends in most run-blocking snaps played despite being the second-lowest rated player at the position after Eric Ebron of Detroit. Weston Richburg was the league’s fourth-worst rated run blocker at center.

Detroit Lions

Only two teams, the Atlanta Falcons and Los Angeles Rams, allowed more points per trip inside the 20-yard line than Detroit (5.38). No eventual Super Bowl champion since 2008 has ever ranked worse than 15th in red-zone points allowed.

Most of the scoring is attributable to the Lions giving up the most passing touchdowns in the red zone (28) this season. The team’s pass coverage finished the season rated as the seventh-worst unit in the NFL. Three of their defensive backs playing at least 200 snaps – Johnson Bademosi, Rafael Bush and Quandre Diggs – were saddled with negative pass-coverage grades, as were linebackers Kyle Van Noy, Antwione Williams and Tahir Whitehead. Whitehead, it is worth noting, played the third-most pass-coverage snaps for Detroit and ended the season as the fourth-lowest rated linebacker at the position per Pro Football Focus.