While the NFL universe has been breathlessly gushing over the New England Patriots offense for nearly two decades, the Pats defense is usually described with an old chestnut of coachspeak: “Bend but don’t break.” For years, Patriot defenses have allowed heaps of yards but denied points by tightening in the red zone, and this season’s iteration is no different. But on a game-by-game level, this Patriots defense has taken on a new quality: They bend early, then straighten themselves out at halftime.

There’s a huge difference between the Pats defense that takes the field at the beginning of the game and the one that walks off the field (usually) victorious. Including both playoff games, the Patriots’ first-half averages of 5.85 yards per play (30th) and 10.06 points allowed (11th) dropped to 5.43 yards per play (22nd) and 8.28 points allowed (2nd) in the second half. This suggests that even if Nick Foles and the Eagles move the ball early and put up points on Sunday, there’s reason to believe Bill Belichick and defensive coordinator Matt Patricia will draw up a way to stop them before Justin Timberlake is finished bringing sexy back. Just what kind of midgame adjustments are the Patriots making? Let’s examine the last two games.

Against the Tennessee Titans in the divisional round, New England seemed to come in with a concrete game plan: Counter Tennessee’s running-back-and-tight-end heavy offense by stacking the box with defenders and playing tight man coverage. They also used a spy on quarterback Marcus Mariota to contain his running ability.

Per ESPN’s Sports & Information Group, the Patriots had at least eight defenders in the box on five of 16 first-quarter Tennessee snaps. But the Titans pass-catchers were able to get open quick enough to give Mariota options. Backpedaling Pats linebackers failed to get enough depth to cover intermediate seam and out routes. Mariota posted a 99.3 first-quarter Raw Quarterback Rating, and the Titans averaged 6.75 yards per play.

After the Titans found the end zone on their second drive, the Patriots stacked eight in the box on only two snaps out of the remaining 45. With more defenders dropping into coverage, the pass rush was significantly more effective. Watch on this key third-quarter 3rd-and-7, arguably the Titans’ last best chance to get into the game, as Mariota has no place to throw or run:

Mariota was sacked eight times on 45 dropbacks over the course of the game. His QBR over the final three quarters was a miserable 19.7, while the Titans offense netted just 3.53 yards per play.

In the AFC Championship Game, the Jacksonville Jaguars got off to an even stronger start. With a mix of power running and downfield throwing, they jumped out to a 14-3 second-quarter lead. Quarterback Blake Bortles was devastating on play-action passes in the first half, going 8-for-8 for 114 yards and a perfect 158.3 passer rating on throws with run fakes.

After halftime, the Patriots took it away. New England did this, to some extent, by doing the opposite of what they did to Tennessee: sending extra defenders, stuffing the power run and forcing Bortles to make quick decisions.

Here’s an example in the third quarter, where the Jaguars were facing 2nd-and-10. At that down and distance, either a run or a pass would make sense. So the play-action pass could be an effective option, as it had been throughout the first half:

The Patriots decide to risk the Jaguars pass-catchers getting open deep and here press both wideouts with their outside corners. Two linebackers drop into coverage, and behind them is a single-high safety.

Everyone else blitzes, including slot corner Malcolm Butler. Bortles play-fakes to the fullback, then sets up to pass. But tight end Marcedes Lewis fails to recognize the blitz from Butler until it’s too late. Tailback Leonard Fournette, intending to pick up Butler, realizes too late that Lewis let defensive end Trey Flowers through. Soon Bortles is swamped and sacked.

The Jaguars called six other play-action passes in the second half, per ESPN Sports & Info, and Bortles completed just three of them. His second-half passer rating was 69.1, and his QBR was 42.7. The Jags offense averaged 4.34 yards per play in the second half, down from 6.81 in the first. They added just two field goals to their first-half scoring, turning a 14-3 lead to a 24-20 loss.

So what will the Patriots try to take away from the Philadelphia Eagles?

The easy answer would be “whatever the Eagles manage to do well.” In their upset of the Minnesota Vikings in the NFC Championship Game, the Eagles did practically everything well — but above all, quarterback Nick Foles stayed calm in the face of pressure and attacked the Vikings secondary deep.

If the Patriots try to attack Foles the way they attacked Bortles in the second half, it might go badly. Instead, Belichick and Patricia will likely drop into safe zones and wait for the Eagles to reveal their plan — perhaps using red-hot receiver Alshon Jeffery to attack a Patriots secondary that finished 26th against No. 1 wideouts in Football Outsiders’ Defense-adjusted Value Over Average.

Whatever Eagles head coach Doug Pederson’s plan is, he’d better have a Plan B.

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