by Derrik Klassen

"Different" does not have to be "new." Offenses based out of two backs in the backfield, a tight end, and just two wide receivers are almost extinct in today's NFL, but Bill Belichick and the Patriots do not abide by the normal rules. Through many iterations of their offense this year (including a more wide-open stint with Josh Gordon), the Patriots settled on a 21 personnel approach that works for them. The heavier, condensed formations look like a portal to the mid- to late 2000s, but they are as modern and effective as any other new-wave offense.

21 personnel offense spells bad news for the Los Angeles Rams defense. In fact, the Rams have been among the league's worst defenses versus two-back formations since Week 12, according to Sharp Football Stats. The Rams allowed the third-highest success rate against two-back offenses over that span (59 percent), including 11.2 yards per pass attempt and 6.4 yards per carry allowed.

That kind of shoddy run defense will likely prove to be an issue versus the Patriots, especially given that New England has the tools to make that number even worse. Not only do the Patriots have an offensive line talented enough to somewhat mitigate the star duo of Aaron Donald and Ndamukong Suh, but they can mold their run game to slow L.A.'s defensive tackles down. Expect the Patriots to trap and fold to make Donald and Suh think twice about flying up the field.

Below is an example of what the Pats might look to do on Sunday. The formation is set to the right with the tight end and fullback both lined up to that side. Upon the snap, both backs and the quarterback open to the right, indicating what typically would be something like insert zone. However, the Patriots shuffle around their blocking assignments and effectively wash out the Chargers' two interior defenders with unlikely blockers.

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Right guard Shaq Mason (69) "folds" around center David Andrews (60) and allows Andrews to run the shaded zero-technique out of the play as his momentum carries him to the right. Additionally, right tackle Marcus Cannon (61) intentionally bypasses the 3-technique in the area Mason vacated, instead flowing up to the linebacker. Fullback James Develin (46) ends up taking out the 3-technique. With all these things working together, the Patriots create a situation where the Chargers' defensive tackles are running themselves out of the play and giving running back Sony Michel (26) a sweet cutback lane.

In addition to various folds and traps to pray on Donald and Suh's aggression, the Patriots will likely turn to draw plays. Draw plays out of two-back personnel sets have become regular for the Patriots this postseason. Like folds and traps, draw plays can make aggressive interior defenders pay for flying off the ball. The Patriots got the Chargers and Chiefs a handful of times this way, including once for a Michel rushing touchdown against the Chargers.

The Patriots use all of these aggression deterrents to slow down an opposing pass rush without committing more blockers in the pass game. By making defenses second-guess themselves and deal in uncertainties, the pocket becomes a more comfortable place for quarterback Tom Brady to reside.

The deception only increases when examining the Patriots' pass offense. According to Sports Info Solutions charting (subscription required), the Patriots used the fourth-highest rate of play-action passes in the NFL at 29 percent and did so with a league-best 9.9 yards per attempt. Again, the Patriots' strength bodes poorly for the Rams' defense. Over the course of the year, the Rams were the second-worst play-action pass defense, giving up 8.8 yards per pass attempt.

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Again we see 21 personnel for the Patriots -- shocking. For this play, both of the Patriots' receivers are to the right of the formation, with the tight end and fullback to the left. The left guard and fullback cross the formation to the right upon the snap, giving the illusion of a counter run. The run action sucks in the linebackers and the cornerback playing off the left edge. Slot receiver Julian Edelman (11) then gets to work across the field into free space and only has to worry about the deep safety, whom he sets up with a deep stem just long enough to snap it off and beat him across the field.

Granted, the Rams have proven willing to move their outside cornerbacks across the formation to follow receivers, which they may do against Edelman in these scenarios. However, that does not solve Los Angeles' dilemma of susceptible linebackers or a congested interior pocket with a front four that relies on interior pressure. Edelman more than likely gets a good chance to work the middle of the field regardless of the Rams' tendency to follow receivers.

Another portion of the value in New England's two-back sets is the running backs' flexibility to line up or motion out wide. The likes of Rex Burkhead and James White must be respected from a wide receiver position, and they can often expose defensive coverages as result of their pre-snap usage.

Kansas City's defensive structure clearly changes after Burkhead motions out of the backfield. In the first screenshot, it looks as though the Chiefs want to play a one-high defense with man coverage, but they are forced to adjust after the motion. Cornerback Kendall Fuller (23) widens out to match Burkhead, while safety Daniel Sorensen (49) backs off of the tight end to a split-safety alignment and outside linebacker Justin Houston (50) widens out to split the difference between the tight end and slot receiver. Now it looks like the Chiefs want to play either Cover-2 or Cover-4 (Quarters). Of course, Brady takes advantage of the information.

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Brady eyes Sorensen as soon as he gets the snap and knows Sorensen is trailing back into a split-field coverage. In turn, Brady knows the linebackers will be spread thin in their underneath coverages with no safety help down low. From the left side of the formation, tight end Rob Gronkowski (87) immediately cuts underneath the line of linebackers, while the tight end on the right, Dwayne Allen (83), runs a 10-yard sit route to occupy the middle linebacker. The space manufactured between the occupied middle linebacker and Houston gives Brady a clear window to hit Gronkowski for a solid gain.

All of these advantages the Patriots can create through their two-back personnel sets are made better by their ability to simply check the ball down to them and let them go to work. Though the Rams' defense was surprisingly good against running backs in the pass game this year (fourth per DVOA), Saints running back Alvin Kamara proved that a vibrant enough talent can nullify that supposed strength. Kamara ravaged the Rams in the first three quarters of the NFC Championship Game from the slot, on the perimeter, out of the backfield, and as a middle-of-the-field checkdown option. He accumulated 12 receptions and 115 yards on 14 targets over that span. Kamara's production petered out in the fourth quarter and overtime, when he saw just three targets. The Saints felt pressure to throw deeper despite not having the talent to do so. As such, Kamara's impact was negated not by the Rams' defense, but by the game situation. The Rams never showed they had an answer for Kamara and were fortunate the Saints felt the need to go elsewhere.

Nobody would contest that Burkhead and White are the caliber of player Kamara is, but they are both fantastic pass-catchers and will be put in similar positions to succeed by Brady and offensive coordinator Josh McDaniels. White, in particular, may be able to mimic Kamara's short-area quickness and effectiveness in the open field.

The Rams are in an unfortunate situation where they have star power on defense and a generally solid unit, but still have clearly abusable weaknesses. Between a fantastic offensive line; constant motion and pre-snap illusion to disrupt coverage shells; and a two-back base offense, the Patriots have all the right ingredients to attack those Rams weaknesses. That is an exhausting conclusion at this point in the Patriots dynasty, but it is again where the NFL finds itself at the end of the season.