FOXBORO -- The concept really isn't all that difficult to grasp, but it gave the Patriots a hell of a time in last year's Divisional Round game against the Texans.



It's called the "diamond" front, and the Texans have the personnel on their defensive line to turn a simple X's and O's idea into a nightmare for opposing quarterbacks.

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Here's how it works . . .



Take your typical third-down four-man defensive line, with two wide defensive ends and two three-techniques on the interior. Then place a fifth defender right over the center. And make him an athlete, whether it's another defensive end or a linebacker. Someone with some pass-rushing savvy.



The result is one-on-one matchups across the board for the offensive line. Each blocker in a five-man protection setup has one pass-rusher to account for. If the defense plays it right, it will get the matchups it wants.



When the defense is star-studded up front -- as is the case with the Texans -- the one-on-one matchups are pretty mouth-watering regardless of the alignment. Whitney Mercilus on the interior is a problem because of his athleticism. Jadeveon Clowney has length and speed that create issues against shorter-armed guards and centers. J.J. Watt one-on-one with anyone is almost an impossible ask.



Last year, without Watt in the mix, the Texans had great success with the diamond front against the Patriots in the playoffs. Mercilus beat David Andrews with a spin move for a sack out of that alignment. He beat Andrews again in that game, opening things up for Brian Cushing to sack Tom Brady.



Wining one-on-one matchups will be key, the Patriots know, to give Brady a chance in Week 3 at Gillette Stadium.



"Look, we only have so many blockers and they have just as many rushers," Patriots offensive coordinator Josh McDaniels said this week. "At some point, every football game becomes about what you can do, and your individual one-on-one matchup, and there’s no guarantee that you can double-team this guy or that guy. That’s virtually impossible to determine before the ball’s snapped, before they align on defense. They don’t line up in the same spots every play.

"You’ve got to be smart and try to do what you can to move the football -- run, pass, first down, second down, third down, whatever it might be -- against a group like this that’s dynamic at a lot of spots. We’re working hard right now to put together what we want to do."



Where the Texans are able to add a layer of deception to their diamond-front looks is by rushing only three. By showing five at the line of scrimmage and then dropping two of those defenders into coverage, Houston still gets the one-on-one matchups it's looking for (leaving two offensive linemen momentarily blocking air because their assignments dropped) while getting eight bodies into throwing lanes.



It's a similar idea to what the Jets did to the Patriots under Rex Ryan, what the Broncos did to them in the AFC Championship game in 2015, and what the Chiefs did just a couple of weeks ago: Flood the short-to-intermediate area of the field with defenders to force Brady to hold onto the football, and win your one-on-one matchups up front.



Pressure and coverage. Even the best quarterback in football can't help but be stymied by that combination when it works.



According to TheMMQB.com's Andy Benoit, who dropped into Quick Slants the Podcast before the season to detail what he found on the diamond front, the Texans used that alignment six times and Brady completed just one pass for seven yards. He was sacked twice. He threw incomplete three times.



Factor in some of the twists and stunts that Watt, Mercilus and Clowney will combine to run, and life only gets more complicated for offensive line coach Dante Scarnecchia's group. Linebacker Bernardrick McKinney and defensive tackle DJ Reader (now in the Vince Wilfork role) also require attention, Bill Belichick noted this week.



"They can power rush, they can speed rush, good counters, they run games well, good technique players, they're well-coached," Belichick said this week of the Texans front. "[Defensive coordinator] Mike [Vrabel] does enough things to keep you off-balance. [But] I’m not looking out there and saying, 'Well, we've never seen this before.'



"There's some three-man rush, there's some four-man rush, there's some five-man rush, there’s a lot of straight rush, there’s power rush, there’s games, multiple games. You're never sure exactly which one of those things you’re going to get. When you start mixing them together you don’t end up with the same thing repeatedly, so it’s always something else different. A different type of rush, a different type of coverage, maybe players aligned in different positions, even though it might be the same players but just different matchups. They create a lot of problems."



Problems, yes. But not unsolvable ones. Should the Patriots be able to withstand the initial rush out of diamond looks, they could provide Brady with the opportunity to make some plays down the field.



Say, for instance, Andrews wins off the snap against someone like Mercilus. If the Texans drop eight, that may leave someone like Joe Thuney or Shaq Mason freed up to double Mercilus later in the play. With some quick recognition, good communication and a few doubles across the board, Brady might be afforded the time necessary for his receivers to run through the muddled short area of the field and into open spaces deep.



For Brady, potentially having Brandin Cooks, Phillip Dorsett (knee injury suffered in Week 2) and Rob Gronkowski (groin) at his disposal -- none of whom were there for the Texans matchup in January -- won't hurt. But Brady knows he'll have to have his internal clock dialed in. The longer he holds onto the football, the most he's asking of his line against one of the best fronts in the league.



"J.J. is an incredible player. He’s been Defensive Player of the Year how many times? Three or four? Something like that," Brady said on Wednesday. "He’s got speed, quickness, power, he’s got all the moves, got all the counters. He’s just a tough guy to block. Then you pair him with Whitney Mercilus, who’s one of the most underrated players, I think, in the league in terms of rushing the passer to everything that he does to help that team. I know practicing against that guy how good he is.



"And then with Jadeveon, he’s one of the most athletic guys in the league. He does some things that other people can’t do. He’s just size, speed, explosiveness. So all those guys on the same field at one time is a big problem for any offense. You don’t want to be holding the ball too long because you know that they’re going to get home at some point and I think that means we’ve got to really stay on track."



No doubt it will be a chess match. How will Patriots backs factor into protection? How will the Texans move their pass-rush pieces from snap to snap? If Marcus Cannon (ankle/concussion) is unavailable, how do Belichick, McDaniels and Brady provide help for their fill-in right tackle?



The Patriots beat the Texans in the Divisional Round last season, 34-16, but thanks in part to Texans pass-rushers and their diamond front, Brady went just 18-for-38 for 279 yards, two touchdowns and two picks. The memory is fresh.



"They’re going to give us everything we can handle this weekend," Brady said.