Watch Now: Protecting Brady against Eagles D-line (1:19)

Because the New England Patriots are a regular Super Bowl participant, there's been a lot to say about them. In the four years of Key Matchup posts I've written, the Patriots offense has been the focus more than any other unit in the league. 

That's what happens when you're going for your sixth Lombardi Trophy, which would tie the Pittsburgh Steelers for the most all-time. The Patriots hope to achieve that mark with a win over the Eagles in Super Bowl LII on Sunday.

Note: We're running two Key Matchup posts for Super Bowl LII. The other one focuses on the New England Patriots defense vs. the Philadelphia Eagles offense.

Because New England's offense has been the focus so often, a common theme has emerged in all of those previous posts. See if you can spot it.

Jan. 7, 2015

It's no secret that quarterbacks perform worse when under pressure from the opposing pass rush. You hear it on every NFL broadcast and every talking head pre-game show. Good as he is, Tom Brady is no different. He's obviously more than capable of making game-changing plays when hit or hurried -- he's Tom Brady, after all; but on the whole he's not nearly as effective throwing the ball while staring down rushers as he is when he has a clean pocket to throw from.

Dec. 16, 2016

The quick and obvious answer to how the Broncos held Brady in check is the same as the one that has held true for basically all teams that have managed to frustrate Brady throughout his career: They put a ton of pressure on him. Every quarterback performs worse when pressured, and that has been especially true for Brady. 

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Denver actually blitzed significantly less often against the Patriots than against other opponents (as Bill Barnwell noted, their blitz rate in the AFC title game was the lowest single-game rate for a Wade Phillips defense in eight years), but the blitzes they did send were extremely effective.

Denver's corners played tight coverage to take away the short crossers to Julian Edelman that Brady loves so much, while their safeties and linebackers bracketed Rob Gronkowski with double teams. The Broncos bet that they could sit in tight coverage to take away short routes and dare Brady to throw over the top of the defense while still getting pressure without having to use extra rushers to do it. For the most part, the Broncos widened out their defensive splits, hoping to isolate New England's offensive linemen in space and let their guys up front -- Von Miller, DeMarcus Ware, Malik Jackson and Derek Wolfe, mostly -- win their battles one-on-one. It worked more often than not, and the Broncos repeatedly got to Brady before he had time to deliver the ball cleanly.

Feb. 3, 2017:

At the risk of sounding like a broken record within the confines of this Key Matchup series: the blueprint for slowing down the New England Patriots offense has been set for years. The key, as always, is pressure.

Like every other quarterback, Tom Brady is not nearly as effective when under pressure as he is when throwing from a clean pocket. The split in 2016 was not quite as drastic as some previous years, but still it was still apparent: Brady had a 123.0 passer rating from a clean pocket and an 84.9 mark when hit or hurried.

It's important not to go all out to get that pressure, though. Brady is arguably the NFL's best quarterback against the blitz. There is nobody better at identifying where the rushers are coming from, spotting which of his receivers will come open after the snap, and then delivering the ball to that play quickly and accurately. Brady torched defenses to the tune of a 129.6 passer rating when blitzed this season, completing 66 percent of his passes at 9.0 yards per attempt while throwing 16 touchdowns and only one interception.

Those are just three examples of many; and at the risk of once again sounding like a broken record, it is time once again to say this: the biggest key for the Philadelphia Eagles defense in Super Bowl LII will be getting pressure on Tom Brady without resorting to the blitz. 

Find out what SportsLine's advanced computer model has to say about the final score of Super Bowl LII. 

The numbers in 2017 were mostly in line with those from previous seasons -- only he was even better with rushers in his face than in previous seasons. Brady was sacked, hit, or hurried on only 31.4 percent of his drop backs during the regular season, per Pro Football Focus, the eighth-lowest rate in the NFL. Including the Patriots' two playoff games, he completed 70.2 percent of his passes when throwing from a clean pocket and only 55.4 percent under pressure. He had a 105.7 passer rating from a clean pocket and a 95.5 rating when pressured. He was not quite as strong against blitzes as in years past, mostly because he didn't have his best blitz-beater (Julian Edelman) on the field. 

Luckily for the Eagles, they are one of the teams most well-equipped to generate pressure without sending extra rushers after the quarterback. Philadelphia has a deep, versatile defensive line, with seven players that get regular snaps and are all capable of beating the man in front of them in order to muddy up the pocket. Some of them are purely edge guys, some are interior-only players, and some can move around the formation. Together, Fletcher Cox, Timmy Jernigan, Brandon Graham, Vinny Curry, Derek Barnett, Chris Long, and Beau Allen form one of the most formidable defensive fronts in the league. 

The Eagles had only 38 sacks during the regular season, but that figure misrepresents just how strong their pass-rush was. Their pressure rate of 41.5 percent, per Pro Football Focus, was considerably above-average; and made even more impressive by the fact that they had one of the lowest blitz rates in the NFL at only 23.4 percent. 

That ability to generate pressure without blitzing was wildly important during the Eagles' two NFC playoff wins. In the divisional round against the Atlanta Falcons, Philly got to Matt Ryan on 16 of his 39 drop backs. That's a 41.0 percent pressure rate. They Eagles sent only eight blitzes in that game, a 20.5 percent rate. Their NFC title game performance was even more impressive. Case Keenum was only sacked once, but he was under pressure on 24 of his 50 drop backs. That's a 48 percent pressure rate, which would have led the league this season and almost any other. How many blitzes did the Eagles send to get all that pressure? Seven. That's it. 

The Jacksonville Jaguars attempted to execute a similar game-plan against the Patriots last week, and for a while, it worked. They held the Patriots to just 10 points through three quarters, and Brady 17 of 25 for 152 yards and no scores when the Patriots got the ball back two plays into the fourth quarter. To that point that Jaguars had gotten pressure on only 22.2 percent of Brady's drop backs, but their conservative approach was working. And then it fell apart. The Jags got pressure on only two of Brady's 15 fourth-quarter drop-backs, and he proceeded to tear apart the best secondary in football. 

Philadelphia's corners aren't quite as good as Jacksonville's -- nobody's are. Jalen Ramsey and A.J. Bouye were arguably the two best corners in the league in 2017. That said, Ronald Darby and Patrick Robinson form a strong 1-2 punch, with Darby on the perimeter and Robinson in the slot. The weakness in the secondary is Jalen Mills, and it wouldn't be a surprise to see the Pats try to attack him with a double-move. (He's been beaten by several of them throughout the season.) In order to get to something like that, though, they need good enough protection. If the Eagles are able to minimize their greatest weakness on the back end, it'll be by working through their greatest strength. 

The Eagles like to rotate their defensive linemen in order to keep them fresh, which should help protect against the kind of late-game drop-off the Jags experienced last week. Each of their top seven defensive linemen played more than 40 percent of the defensive snaps this season and none of them played more than 70 percent. The players in best position to pick up heavy pressure this week will likely be Curry and Barnett, who split the snaps on the right side of the line. Patriots left tackle Nate Solder was the team's most vulnerable lineman during the regular season, and he gave up two of the three hits on Brady last week as well. Getting interior pressure against New England is arguably even more important than edge pressure, though, so Cox, Jernigan, and Allen will need to be at the top of their respective games as well. 

If it seems unlikely that any team would generate enough pressure to completely throw the best quarterback of all time off his game in the biggest game of the year, well, it is. But it's happened before. And it can happen again. And for the Eagles to win, they'll likely have to become the latest team to figure out a way to do it.