As an offensive revolution has taken over the NFL in recent years, the league’s most dominant units have shared a through line: variation. The Patriots, for instance, have become known for mixing up their personnel packages and formations to keep defenses off-balance. This season, New England used 21 personnel (a grouping with two running backs, one tight end, and two wide receivers) on 31 percent of its offensive plays, the second-highest mark in the league. The only team to use that grouping more often was the 49ers, whose head coach, Kyle Shanahan, has relied on dizzying combinations of personnel groupings throughout his decade as an NFL play-caller.

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Look at the data on teams’ personnel groupings this season, and it’s clear that the Saints and Eagles—both led by progressive play-calling head coaches—are also outliers. No team used 12 personnel (a grouping with one running back and two tight ends) more often than the Eagles, at 44 percent of their offensive plays. The high-flying Chiefs ranked third, at 27 percent. Coach Sean Payton and the Saints are all over the map with their personnel packages, ranking 30th in their usage of 11 personnel (one running back, one tight end, three wide receivers), the league’s most popular grouping. The lesson from those numbers is that most of the NFL’s top creative minds use every method available to make their offenses look different from snap to snap. That’s what makes the Rams’ strategy this season so fascinating.

“Gurley could be outside, in the backfield, anywhere on the field. ... So if you’re trying to double a guy or take a guy out of a game plan, it’s difficult to do because they’re everywhere.” —Aaron Kromer, Rams run game coordinator

In 2018, coach Sean McVay’s team used 11 personnel on an astounding 90 percent of its offensive plays. No other team finished higher than 80 percent, and only six used 11 personnel on more than 70 percent of their snaps. That discrepancy is stunning.

McVay has embraced the most extreme offensive method of any coach in the NFL—working almost exclusively out of the simplest personnel package—and has thrived because of the way he’s done it. Traditionally, coaches have gotten roasted for an overreliance on 11 personnel. In 2016, then–Giants head coach Ben McAdoo used 11 personnel on 92 percent of his team’s offensive snaps, making New York’s unit equal parts basic and predictable. These Rams, on the other hand, trot out the same 11 guys for seemingly every offensive play, and they’re successful because that’s the only thing that remains consistent from snap to snap. McVay’s attack features a barrage of motion and wonky uses of players at different positions. Defenses know what they’re going to get—they just don’t know how they’re going to get it.

Whereas some NFL teams have playbooks as thick as phone books, the Rams have assembled one of the league’s most dangerous offenses primarily by going the other way. Their approach is streamlined. In some ways, McVay will trot out the most predictable scheme in the NFL in Saturday’s divisional round matchup with the Cowboys. Look closer, though, and it’s clear that even if the players don’t change, this Rams offense is anything but simple.

The Rams arrived at this strategy sort of by accident. McVay spent his early days in the league working under Jay Gruden and Kyle Shanahan in Washington, where the offenses featured a variety of personnel groupings. When McVay accepted the head job in Los Angeles in 2017, his plan was to implement an array of personnel packages that would make the Rams offense difficult to prepare for. After all, that’s what he knew.

Part of any new staff’s acclimation process includes learning the ins and outs of its players, and all of the changes to the Rams’ roster that offseason only exacerbated the challenge. Namely, general manager Les Snead revamped the team’s entire receiving corps. He signed former Bills wideout Robert Woods to a five-year, $34 million deal in free agency. A month later, the Rams snagged prolific Eastern Washington receiver Cooper Kupp in the third round of the draft. And the group wouldn’t be complete until Snead pulled off a trade with the Bills to acquire former top-10 pick Sammy Watkins that August. When McVay and his staff originally devised their plan, they did so without knowing the sort of upgrades that were coming across the offense. “Until you play a game, you don’t really know who you have,” Rams run game coordinator Aaron Kromer says. “Shoot, you’re trying to put the players in the best position to win. You use what you know, and as you develop throughout the year, you’re saying, ‘All right, this guy’s good at this, this guy’s good at that.’”

The shift to this version of the 11 personnel strategy didn’t happen right away. Over their first three games of the 2017 campaign, the Rams used the grouping on just 58 percent of their snaps. But during weeks 4 and 5, that figure jumped to 74 percent. From weeks 6 through 10, it climbed to 78 percent. And finally, from Week 10 on, it jumped to 94 percent, completing the unit’s transformation into the offense we see now. Rather than being forced into using this grouping because of injury or necessity, the Rams settled on this approach because it repeatedly got results. The staff slowly learned that despite McVay’s intentions to field an offense with multiple groupings, the team would be doing itself a disservice by not keeping Woods, Kupp, and Watkins on the field with star running back Todd Gurley and a single tight end. “As a [staff],” Kromer says, “we’ve decided that’s the best group we have. The fastest way to move fast is to use your fastest guys. And those are our fastest guys.”

After fully committing to such a drastic concept, the challenge became mastering how to manipulate opposing defenses with the same 11 players on the field. For most NFL teams, swapping personnel groupings helps to extract information about the defense and avoid establishing obvious tendencies. Eschewing that strategy means the Rams have had to devise creative ways to do both.

One of their methods is to use jet motion more than just about any team in the NFL. The Rams use many different types of pre-snap movement, but the frequency with which receivers tear across the formation is distinct. Los Angeles used jet motion on 17 percent of its offensive plays this season, the highest mark in the league, according to Sports Info Solutions.

Sending receivers in jet motion accomplishes several objectives for McVay’s offense. In some cases, it allows the Rams to put an opponent’s linebackers on a string, getting them to shift directly before the snap—creating running lanes and improving blocking angles. L.A.’s pre-snap chaos has other applications, too. The constant onslaught of motion is undeniably disorienting for defenders. “It’s a lot of eye candy for them to see,” Woods says. “They don’t know if they have to knife downhill, play the sweep, play pass.”

Defenders need to sort through all of those options in an instant, while also accounting for a player barreling full speed toward the perimeter. That can create moments of ever-so-slight hesitation on the part of the defender, and those moments can make all the difference. “It makes our job blocking the linebackers and blocking the ends a whole lot easier because they have to respect everything that our offense does,” Woods says.

“A lot of [the offense] is based on different formations and motions and shifts. There’s different ways to add variety, even if it’s not personnel groupings.” —Sean Mannion, Rams backup quarterback

Along with the pre-snap movement, McVay’s team also presents defenses with an assortment of alignments. Every skill-position player on the Rams roster—from Woods to Gurley to tight end Gerald Everett—can line up at virtually every spot within the formation. For the receivers, that can mean spreading out wide or bunching in tight to the formation in some type of stack. By shifting their pass catchers around, the Rams uncover different facets of the defense. “Gurley could be outside, in the backfield, anywhere on the field,” Kromer says. “I think that’s where it’s a little bit more advanced as well. You never know where the guys are going to line up. So if you’re trying to double a guy or take a guy out of a game plan, it’s difficult to do because they’re everywhere.”

Take quarterback Jared Goff’s game-winning touchdown pass from the Rams’ thrilling 54-51 win over the Chiefs in Week 11. Facing a first-and-10 from Kansas City’s 40-yard line, Los Angeles came out in a shotgun formation that resembled most of the sets it uses. Wide receivers Brandin Cooks and Josh Reynolds were both aligned in a tight stack to the left, with Woods alone in the slot on the right. But there was a twist. Rather than setting up camp near one of the offensive tackles, tight end Everett split wide right as a receiver. Chiefs safety Daniel Sorensen followed Everett to the sideline, signaling to Goff that the defense was in man coverage. After taking the shotgun snap, Goff immediately lofted a deep throw down the sideline that resulted in a 40-yard touchdown for Everett.

“People get information in different ways,” Rams backup quarterback Sean Mannion says. “Some people might have a lot of variety in personnel. We use one personnel grouping, for the most part, but a lot of [the offense] is based on different formations and motions and shifts. There’s different ways to add variety, even if it’s not personnel groupings.”

The Rams’ approach requires more window dressing than those of other teams, but their steadfast commitment to 11 personnel also comes with a few inherent advantages. By keeping three receivers on the field, L.A. has an easier time forcing opposing defensive backs to honor every inch of the gridiron. Kromer served as an assistant to Payton in New Orleans from 2008 to 2012, and says those Saints teams would often use stacks packed tight to the formation to create two-way releases for receivers. The Rams use a similar tactic on nearly every one of their pass plays. “We force [the defense] to communicate,” Woods says. “They do take away something, but they do give something. … I know that we’re condensed, but they still have to respect every single cut.”

Those tight alignments also allow the Rams to resemble heavier personnel packages in the running game without taking any speed off the field. And it helps that all of L.A.’s receivers—Woods, in particular—are willing and able blockers.

Some opposing teams have attempted to combat the Rams offense by staying in base defense, despite the mismatches that might create in the passing game. By doing this, teams avoid getting locked into a nickel package (featuring three cornerbacks and two linebackers), which would allow Gurley to gash the defense all game long. Gurley faced eight or more men in the box on just 8.2 percent of his carries this season, according to NFL Next Gen Stats; that’s the third-lowest rate in the league, behind 5-foot-6 Bears flash of lightning Tarik Cohen and 200-pound Eagles running back Wendell Smallwood. Gurley is a 230-pound battering ram who sees more rushing volume than any player aside from Ezekiel Elliott. Countering him with light boxes makes no sense, but given the Rams’ three speedy receivers to worry about, opposing teams are often left with no choice. “What we’ve learned is that when teams play base against us,” Kromer says, “we get them out of it pretty quick.”

The real strength of the Rams offense is that all of their plays look identical for the first few steps. Trying to decipher how a plan is going to unfold can cause nightmares for defenses. And having the same players on the field for nearly every play gives Los Angeles a leg up when it comes to play-action. Only Baltimore’s Lamar Jackson used play-action on a higher percentage of his throws in 2018 than Goff (34.6 percent of dropbacks), whose 10.0 yards per attempt on those throws ranked fourth out of 37 qualified quarterbacks. Compare that to the 7.5 yards per attempt Goff averaged on non-play-action throws, and it’s easy to see why the Rams lean so heavily on that concept. The team’s dedication to 11 personnel has keyed his turnaround from rookie disappointment to pilot of one of the league’s most devastating offenses.

In McVay’s offense, the running game works for the passing game, and vice versa. And all of that is made possible by formations that don’t tip his hand. “Whether or not we’re running the ball or passing the ball, it looks the same,” center John Sullivan says. “We don’t switch personnel groups to do things, so [defenses] can’t figure out tendencies. We do it all out of one, so you have to prepare for everything all the time.”

Over the past two seasons, the Rams have faced just about every defensive tactic in the book. Some teams have thrown three linebackers at them, in an attempt to slow down Gurley. Others have been content to play nickel, hoping to match the Rams’ offensive speed. Sullivan says that recently, they’ve seen teams use some 5-1 jam alignments, in which a defense stays in nickel while putting more bodies on the interior of the line of scrimmage. Despite all of this experimentation, though, few defenses have succeeded.

“Whether or not we’re running the ball or passing the ball, it looks the same. We don’t switch personnel groups to do things, so [defenses] can’t figure out tendencies.” —John Sullivan, Rams center

The Rams did hit a minor skid in early December, sputtering early in a 30-16 win against the Lions before putting up just six points against the Bears the following week and then losing 30-23 to the Eagles. Kromer claims that nothing any of those defenses did was revolutionary. But given the team’s prolific standards this season, any drop-off is glaring. “People didn’t have this expectation of our offense last year,” Kromer says. “So everything good we did was above and beyond. And if something bad happened, that was supposed to happen. Now we’re supposed to score 50 points a game, so the pressure’s on to keep going.”

On Sunday at the Coliseum, the Rams will face a Cowboys defense that has been scorching hot over the second half of the season. Aside from a meaningless Week 17 game against the Giants, the Cowboys haven’t given up more than 23 points in a contest since November 5. As Dallas has prepared to face the L.A. offense this week, defensive players have recognized just how rare the Rams’ methods are. “They really get your eye to wander,” safety Jeff Heath said.

This weekend, that unit will face a challenge unlike any in football. The Rams are at the forefront of the NFL’s offensive explosion, and they’re doing it via an approach all their own. “I think what people find is they’re gonna need to do something a little bit different,” Kromer says. “People every week are going to try to change their coverage a little bit or change the way they get to their plan. As the game goes, we roll, we figure it out, and we keep going.”