The Pats Have Gotten By With Bad Defenses, But This Is Ridiculous Too bad Tom Brady can’t play on both sides of the ball.

The New England Patriots are usually immune to Super Bowl hangovers; you don’t win five championships and 14 division crowns in 16 seasons by resting on laurels. But early in this year’s title defense, the Pats find themselves with an uncharacteristic 2-2 record — including 1-2 at home, where they’re usually invincible. Bill Belichick and Tom Brady have been doing this thing long enough that Pats fans shouldn’t be fully panicked quite yet — our NFL predictions still give them nearly a 70 percent chance of making the playoffs — but it’s worth dissecting these four games to see if they represent a momentary hiccup, or if the champs are truly in trouble.

If someone had told you before the season that the Patriots would struggle through four weeks, it would have been logical to assume that the 40-year-old Brady had started to show his age, like so many QBs have before. But the funny thing is, Brady has been nothing less than outstanding so far: According to adjusted net yards per attempt, this is shaping up to be the most efficient season of Brady’s career, which is remarkable for a QB who might be the best in history.

Brady has even done it despite having to abruptly adjust his quarterbacking style in the wake of a season-ending injury suffered in the preseason by top 2016 target Julian Edelman. Without Edelman running underneath routes to stretch defenses horizontally, Brady’s average air yards per attempt has skyrocketed from 7.5 a year ago to 10.0 this season. After throwing only 19 percent of his passes more than 15 yards downfield last season, Brady now airs it out 28 percent of the time, with newcomer Brandin Cooks ranking fourth among all NFL receivers in air yards per target. And yet, in spite of the more difficult throws, Brady is also completing 66.5 percent of his passes, one of the best rates of his career. He hasn’t been perfect — he’s taking a lot of sacks despite facing less pressure in the pocket — but Brady has done some of his best-ever work under center so far in 2017.

Because of Brady’s heroics, the Patriots have easily been the best offensive team in football thus far according to expected points added (EPA), generating 52.2 net points when they have the ball (nearly 7 more than the second-place Chiefs). Trouble is, they’ve also been the league’s worst defensive team. And it’s not even remotely close.

The Pats’ defense is yielding 48.8 net points when the opponent has possession, 13.1 more than the second-to-last Titans. If that holds up, it would be the first time since 2006 for the same team to finish first in one category and last in the other. (No team has ever ranked first in defense and last in offense.)

The worst defenses since ’06 Most expected points added (EPA) allowed per game by NFL defenses, 2006-17 EPA YEAR TEAM RUSH PASS TOTAL 2017 Patriots +0.4 -12.4 -12.2 2015 Saints +0.8 -11.2 -11.2 2008 Lions -2.5 -7.5 -9.9 2016 Browns -1.1 -8.6 -9.5 2010 Texans -0.4 -9.2 -9.5 2017 Titans -0.2 -8.8 -8.9 2008 Broncos -1.9 -6.4 -8.3 2010 Jaguars -1.0 -6.9 -7.7 2014 Saints -2.1 -6.1 -7.7 2011 Buccaneers -2.3 -4.9 -7.7 Total EPA may not match passing + rushing because of penalties. Source: ESPN Stats & Information Group

But even that by itself understates just how bad the Pats’ D has been this season. So far, New England is allowing a staggering 116.5 passer rating — essentially turning every opposing QB into Peyton Manning — and has also been carved up for 5.1 yards per carry. With an average of 12.2 EPA allowed per game, the Pats’ defense is tracking to be the single most porous D of the past 12 NFL seasons.

New England has been in a similar position before. In 2011, the Patriots were roughly as good on offense as they’ve been this season — they ranked third in offensive EPA behind the Saints and Packers — and although they weren’t as much of a defensive dumpster fire as the 2017 edition has been, they still ranked eighth-to-last in EPA allowed and had the league’s sixth-worst pass defense.

That team went 13-3, finished third in point differential (+171) and eventually made it to the Super Bowl before being upset by the New York Giants. This year’s version, by contrast, is barely outscoring opponents (they have a +1 point differential) and might be lucky to extend the franchise’s streak of winning a double-digit number of games to 15 years.

So how were the Pats able to survive this kind of all-offense configuration in the past? By bending but not breaking. As we noted before the Super Bowl in February, one of the hallmarks of Belichick’s Patriots has been a defense that readily yields yardage but refuses to let opponents ultimately convert ball movement into points. From 2001 to 2016, the Pats’ average ranking in yards allowed was 16.1, while their average ranking in points allowed was 7.7; they ranked better by points allowed than yards allowed 14 times in those 16 seasons.

The gap was a function of several important factors, including forcing opponents to drive from the deepest field position in the league, grabbing the most takeaways per drive of any team and summoning the league’s third-best goal-to-go defense (i.e., the rate of touchdowns allowed per drive that contained a down with the goal to go). These were all markers of strong situational defense — meaning that the Patriots’ D would play better the more heavily the situation determined whether they would allow points or (ultimately) win the game.

The Patriots’ D is bending — and now breaking Key defensive metrics for New England 2001-2016 2017 CATEGORY NFL RANK AVG. VALUE NFL RANK AVG. VALUE Touchdowns allowed per drive 3 17.0% 32 31.1% Takeaways per drive 1 15.7% 12 11.1% Opponent’s avg. starting field position 1 27.4 3 25.9 Red zone efficiency allowed 12 52.0% 27 64.3% Goal-to-go efficiency allowed 3 64.5% 30 100.0% Opponent yards per point 1 18.0 22 14.3 Source: ESPN Stats & Information Group

Those same numbers haven’t exactly been on-brand for the Pats so far this year. Although they’ve still forced opponents to drive from the league’s third-worst field position, their takeaways per drive have slipped to 12th, and their goal-to-go efficiency has fallen to 30th. And no defense has yielded more touchdowns per drive — the most elemental sign of whether a defense is bending or just flat-out snapping into pieces.

Indicators of a defense’s ability to bend and not break are notoriously noisy, so the Patriots may very well rediscover their usual form before long. But by the same token, it was remarkable that the Pats’ D was able to survive as long as it had with such fickle metrics serving as strategic cornerstones. Given the team’s dynastic track record, nobody should think about counting New England out yet — particularly as long as Brady keeps playing at such a high level — but with their usual defensive formula disrupted and their home-field aura shaken, the Pats suddenly have more issues to address than they’re accustomed to.

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