How NFL defenses are evolving to stop the boot-action explosion

In the era of McVay, Shanahan, Stefanski and LaFleur, the keeper is king. What are defenses doing to stop it?

Say it with me: We’re living in a wide-zone world. The NFL is now the league of Sean McVay, Kyle Shanahan, Kevin Stefanski, Matt LaFleur, and all of the branches that have fallen off those trees and drifted throughout the league.

This is the era of the horizontal-stretch. Outside-zone, split flow, deep overs, intersecting crossing routes, jet motions, orbit motions, ghost motions, and oh so many play-fakes and boots. Over the past five or so years, those have been the staples of the modern pro-offense. All with the same goal: Get the defense to flow horizontally before you try to him them vertically for an explosive play.

The thorniest questions that has faced DCs as the horizontal-stretch Svengalis have made their way through the league: How to defend the boot action?

Bootlegs are nothing new. Nothing in football is new, in the literal sense. Coaches iterate on old ideas. They find success. Whoever is on the other side of the ball finds a counter. The new idea becomes an old idea. It cycles out. A new idea takes hold. Rinse. Repeat.

Yet the rebirth of the outside-zone-then-boot idea has led to one specific change: the boot-action is no longer a specific down-and-distance call. It’s no longer about moving the chains on third down, or bluffing on early down to steal ten yards. The boot-action has become the go-to way for the league’s most prominent offenses to hit explosive plays.

McVay, Shanahan, and co, didn’t invent the tactic, but they’ve weaponized it to an unprecedented level – both riding fun-n-gun offenses all the way to Super Bowl until they ran into, surprise, Bill Belichick. Sprinkling some pre-snap sugar onto tried-and-true designs – motions, shifts, and all-manner of at-the-snap fun-and-games – has turned the ‘keeper’ from a chain-mover into the shot-play design. It’s the base around which all outside zone teams are trying to hit ‘explosives’.

And the NFL is a league of explosives. Hit as many as you can; stop as many as you can. That’s it. In the passing era, that’s the entire ball game. When you’re not trying to hit a shot play, you best be doing something to set up the next one.

Last season, four of the top-six leaders in bootlegs played in the Divisional Round of the playoffs, per Sharp Football Stats – and all faced off against one another. McVay and the Rams ran 94 (!) keepers last season, per Pro Football Focus, by far the fattest mark in the league.

The shift towards the McVay doctrine was a league-wide answer to the cover-3/man-free defenses that had blossomed over the course of the last decade – you can read more about that here. Everyone was mimicking the Seahawks three-match style to some degree, playing with a single deep safety and then playing a pattern-matching version of cover-3 underneath or man-to-man coverage across the board.

The confuse-and-clobber McVay/Shanahan approach was hand-crafted almost solely to conflict that single-deep safety. Passing concepts were built to attack the seams. Play-action was used to a mind-bending degree, hoping to see the linebackers (and perhaps the safety himself) cheat towards the line of scrimmage, with throws disappearing over their heads as soon as they committed to the run. Play-fakes and added backfield eye candy would (and does) muddy the linebackers read.

It’s not overly complex stuff, but it’s proven to be mighty effective. The Rams, Packers, Browns, and Titans, the darlings of the wide-zone world, have committed wholeheartedly to bludgeoning people with outside-zone, building their dropback passing game, play-action sets and boot-action designs out of the same pre-snap looks. The hope is to pin people in a single deep-set or force man-coverage. From there, the coaches use deep overs, crossing routes and so-called man-beater (stacking receivers, motioning receivers, crisscrossing routes) to bust man-coverage principles. Adding in play-fakes, motions and the eye candy helps create conflict at all three levels for the defense. Where is the ball? Where are the receivers? Where the bleep is everything going?

The use of the boot has steadily trickled up across the league. You know the deal: The quarterback, line, and back set up like it’s outside zone. Everyone kicks one way. It looks, reads, smells, feels like outside-zone. Only the quarterback keeps the ball, rolls to the outside, away from the pass-rush, and then surveys the landscape.

Traditional boot-action concepts are built like any old ‘flood’ concept: there’s a deep route, an intermediate route, and a short route. In the modern game, with almost all just about quarterbacks mobile enough to be a perimeter threat, the quarterback is – as coaches like to say – his own checkdown. If nothing is open, he can carry the ball himself.

(This, by the way, is why should be rightly excited/worried — delete as necessary — about the future Shanahan-Trey Lance partnership. We’ve yet to see one of the horizontal-stretch gurus paired with a genuine perimeter rushing threat.)

You know how the rest goes, too. Usually that quarterback rolls, opens up his hips and fires to a receiver swooping across the field. The defense bites one way, the ball flies the other way:

The old-style keeper was used as a way to get the quarterback out of the pocket and rolling away from the pass-rush. It also split the field in half, limiting exactly what and who the quarterback had to read. And while teams would vary the route combinations, the overall idea was the same: A three-level concept, with deep route stretching the top of the defense and the quarterback looking, primarily, to the intermediate route.

That remains the case for a bunch of teams. But Shanahan, McVay and company have built in a series of cover-3/man-free specific beaters, while adding the option for receivers to break their routes to wherever they can find space further down the field.

Defenses have struggled to keep up. The old way of doing things, of honoring the run, of building a traditional force-and-contain run-fit structure has left them vulnerable to leaving the likes of Aaron Rodgers, Patrick Mahomes and Russell Wilson open on the perimeter, all three happy to take shots downfield from a non-traditional launch point.

Whereas once busting on a boot might cost you a first down, now it’s liable to lead to a touchdown — from anywhere on the field.

After spending a year figuring out the nuances of Matt LaFleur’s system, Rodgers roasted all before him on keepers in 2020. He completed 80.7% (!!!) of his passes on 57 bootleg dropbacks last season, throwing 10 touchdowns to zero interceptions. His 0.48 expected points added per dropback is as good as you will ever find from any quarterback on any single concept.

The LaFleur-Rodgers keeper has proven to be lethal; the 2020 Saints tape, for mature audiences only.

Dennis Allen, the Saints DC, lined up against LaFleur’s Packers ready to play the outside-zone-heavy group as he had always played outside-zone. The Saints sat in a two-deep shell (more on that later), hoping to force the ball out of Rodgers’ hand. The Saints wanted Rodgers to check to a run, which against Aaron Bleeping Rodgers seems like a savvy idea.

And it was – until you remember that the modern game is about layering one concept on top of the other. Watch how the Saints set up early against a typical outside-zone look, with some jet-motion to try to distort the pre-snap picture:

Keep your eyes upfront. The Saints stuff the play. On the right side of the defensive line, the Saints run a quick gap exchange. Their interior man is able to jump out to the left guard’s outside shoulder. From there, he pushes that lineman into the backfield and forces the runner to bounce it, where the Saints defenders can flow to the ball and shut down the play.

It’s a win for the Saints. But LaFleur and Rodgers have their eyes on the backside of the play. As with a ton of boot-action concepts, the backside is ‘naked’. Meaning: The backside edge defender is left unblocked. He is, essentially, blocked by the quarterback. The fear that the quarterback could pull the ball means that the backside defender is forced to sit down and wait to see where the ball is going. The Saints don’t want to bust the run responsibility on the backside contain, so that edge defender shuffles down the line of scrimmage — waiting and waiting — in case the ball squirms its way over to his side. And that is exactly what the Packers were looking for.

It’s a run play, right? The defense is fitting the run first and then reacting to the keeper. These are outside-zone teams after all. They want to run the ball. And so we, as the defense, have to stop it – light box, heavy box, whatever your flavor; get in your gap and shut down the run.

The Packers and LaFleur leverage that idea into easy completions. As the edge defender shuffles and shuffles down the line, it buys Rodgers the time needed to pull the ball, roll into space, and hit shots down the field.

New Orleans is playing that way because that’s how all defenses have treated outside-zone and perimeter running schemes: They’re playing run first:

Not anymore. The Packers torched the Saints in 2020 on boot-action designs. Rodgers was untouched out of the pocket – and there are few things in the league more dangerous than Aaron Rodgers playing out of the pocket with time.

Early this season – and it is, admittedly, a small sample size – astute DCs are triggering on quarterbacks in the outside-run game. ‘Greenlighting’, they call it. As in: You, Mr. Edge Defender, have a green light to hunt the quarterback on each and every play.

There are multiple options. You can do it by scraping the ‘backer and edge defender, similar to how defenses will muddy the ‘option’ portion of a running-option: The edge-defender is responsible for shooting a gap inside, driving across the face of whoever is in front of him. The linebacker reads the movement of the edge defender and slips in behind to fill the spot he has vacated. That allows the defense to maintain its gap integrity against run plays – and it muddies the read for the quarterback on option designs. He thinks there’s no one there, and then suddenly there’s the backside linebacker (or down safety) looping around.

It opens up possibilities for the DC against bootlegs, too. DCs are ‘greenlighting’ the quarterback on wide-zone looks. Meaning: a defender is responsible for attacking the quarterback no matter what. They’re accounting for the quarterback regardless of whether it’s a handoff – just as they do with a run-option. Defensive coordinators are seemingly happy to concede the extra defender in the early phase of the run if it means shutting down the keeper and the explosive play potential that comes with it.

For plenty of teams, the ‘Rat’ or ‘low hole’ defender often operates as a ‘greendog’ defender anyway. If a running back (his responsibility) stays in the pocket to pass block or the quarterback starts to roll, it’s his job to attack. But that doesn’t give quite the initial penetration that a team needs. Instead, DCs have taken to turning the edge defender loose, with a defender scraping over the top to pick up his responsibility as the contain defender.

Track JJ Watt (#99) below:

Ordinarily, that would be considered bad run defense. Watt jumps out of his gap. Any switched-on OC would come back to the same pre-snap look with some kind of trap or counter play directed at the vacated space: Watt jumping out of the line, a lineman walling him off in the backfield, and Derrick Henry breezing into space.

But the Cardinals are playing it differently. They’re Greenlighting the quarterback. They’re more concerned with Ryan Tannehill pulling the ball and rolling on a bootleg than Derrick Henry bouncing an outside-zone run back across the formation.

Over and over again, the Cardinals crashed their end at the quarterback, not down the line of scrimmage. They were making a play for Tannehill, even as the quarterback consistently haded the ball off to Henry. The payoff:

The Titans are in 21 personnel, again – two backs, one tight end. It’s a heavy look. They’re ready to run the ball. At the snap, there’s the classic outside-zone look: the line kick steps in unison to one side of the field. The Cardinals’ front flows with the offensive line… except for that backside defender.

This time it’s Chandler Jones. The Titans are expecting that player to shuffle-shuffle-shuffle down the line, to honor his run fit. But Jones doesn’t, because the Cardinals are – SMACK --Greenlighting the QB. Jones runs on a straight-line to Tannehill, unblocked. It’s a strip-sack, six points for Arizona.

Dennis Allen ran something similar against Aaron Rodgers, Matt LaFleur, and all those funky Packers boot-action designs in Week One of this season. After the mess in 2020, Allen adjusted. Fed-up with gifting chunk plays, Allen instead committed to stopping the keeper.

The end might wriggle down a little, but his responsibility was to attack the quarterback:

The Saints sold out to stop the explosives off of boot-actions. They were not undercutting the flat route; they were chasing Rodgers:

New Orleans stuck in a two-high look, backing an outside corner up way off the LOS — who could drop and drive on the ball or the flat, depending on whether it was a run (outside-zone) or the fake. The main plan: to have the linebackers sit and wait to figure out where the ball was, rather than driving hard towards the line.

A whole bunch of pressure was put on the linebackers. Allen had his linebackers sit, wait and watch. If they get a small gain in the run game until I plug the thing, that’s fine. The job is to stop explosives. Green Bay targets linebackers by getting them to cheat down to the run while a crossing route flys behind them. The linebacker has to press the line, spot the release of the receiver cutting across the formation and then flip-and-find and match the route. The Saints bought their linebackers some extra time; they hung out – no pressure. Plug it when necessary, but not before you’ve checked that the tight end or slot receiver isn’t sneaking across the formation.

It worked. The Saints shut down all of the Packers’ designs. The only time LaFleur and co. were able to shift those linebackers was on a tidy counter-design, with the ‘backers triggering once they read counter rather than outside-zone:

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“The best way to stop boot is to play quarters or blitz,” Coach Vass, host of the Make Defense Great Again podcast and one of the Godfathers of online scheme discourse told The Read Optional.

Teams have adapted their approach upfront. They’re not necessarily blitzing the boot, but they’re exchanging traditional post-snap assignments. On the back-end, things are changing, too. Quarters (and quarters-match) coverage is in the midst of its own renaissance. Teams are shifting to an ever-increasing number of two-deep safety looks to counter-act the Shanahan’s of the world. The Seahawks-style static cover-3/cover-1 is becoming a thing of the past.

“The problem with cover-3 is there are three levels of the defense -- two, really,” Vass says. “What boot does is it sucks you up, and it’s run like ‘Y’ Cross; the number one dropback pass in football.”

“People fuck it up because they have their safety at 12-yards [in cover-3], backing up, and their ‘backers are playing downhill, which they are in cover-3. Now you have a guy at one or two yards and one at twenty yards. It doesn’t take a genius to figure out that getting between the lines is all you need to do.”

“Quarters coverage allows you to break that up.”

“In match quarters,” Cody Alexander wrote in his aptly titled book Match Quarters, “the defense is running a pseudo-man scheme where the back four are either playing man (corners) or bracket concepts (linebackers under/safeties over). Playing a two-high scheme compresses the field and forces the offense to throw outside (low completion throws). The problem with running a true Cover 4 is that the defense is dropping to a spot and not relating to a man. By implementing match schemes, a defense relates to a certain man regardless of the formation while keeping the protection of a quarters scheme.”

There are a whole host of ways to matchup quarters vs. keeper designs. You could use the field safety to drive down and bracket the over route, though the angle offers less of an advantage. You can hand it to the Mike on a push-peel, with the Ni/Sam or edge defender alerting and attacking the quarterback or folding the outside shoulder. Quarters-match coaches will make the call on the field, depending on the alignment or formation of the offense and where that offense puts its most gifted receiver.

At the high school and college level, DCs are cool with singling up and matching the vertical stem of the backside post route. The quarterback is unlikely to throw it there.

At the NFL level, depending on the matchup, that’s no Bueno. Aaron Rodgers and Matthew Stafford can happily make those throws. They have the arm strength and accuracy to throw from anywhere to anywhere. They can throw from funky platforms. They can sling it sidearm. It’s part of why Sean McVay was so giddy to add Stafford this offseason. Suddenly, a defense doesn’t just have to respect the backside post, it has to be terrified of it. Leave that corner on an island vs. Cooper Kupp or Robert Woods (or Van Jefferson, apparently), and you could be in trouble.

As Seth Galina pointed out on PFF.com, McVay and the Rams have taken to booting Matthew Stafford farrrr away from the line of scrimmage, knowing that he has the arm strength to still damage defenses vertically in a way that Jared Goff did not. The Rams haven’t had to scheme up open plays; instead, they’re relying on the skill of their quarterback to sell the fake, beat the edge defender to the corner, and then setup and throw (sidearm, set, whatever) to wherever the ball needs to get too. The defense might play Stafford to a draw or a slight gain a few times, but if the edge defender whiffs or someone busts their assignment, it’s liable to be a six-point error.

Defenses might tweak the look and bracket the backside receiver with the safety to that side, the field safety will then pick up the crosser with help from one of the ‘backers – each of their assignments then being re-jigged. But that opens up one-on-ones and easier completions to the roll-side and offers a natural window for the Y to work through if the quarterback wants to get rid of the ball quickly.

Now you’re asking your Mike linebacker to pick up the route and run in space with the tight end. And what if that tight end is free to adjust his route vs. the defensive look, breaking upfield as he spies the safety pin the post route? You can have your Will dislodge the timing of the route. Or you can let the Will pick up the tight end, with the Mike scraping across to fill the Will’s voided area. But now you risk collisions: the two tight ends picking one another or being forced to freeze, springing the tight end into all kinds of room – which is the whole point of the enterprise.

Let’s return to the Packers-Saints example from earlier. The Packers are running a ‘drift’ concept. There’s a deep in-breaking route (a post or dig), a slide route underneath, a crossing route, and a receiver working against the grain, who will cut across the field to blur the image for the linebackers and safeties before turning upfield on a wheel route.

As the Saints defensive backs and linebackers try to figure out exactly who they have and where the ball is, three defenders collide, two linebackers trying to cover the same player (and get to the same spot) with the team’s nickel trying to shoot across the field to defend the jet-motion-turned-wheel route.

That’s exactly what LaFleur is looking for!

The Saints’ structure remained solid, however. Allen had extra protection on the back-end by way of two-deep safeties, meaning the wheel route wasn’t open long enough for Rodgers to do damage. And it’s not like the quarterback had much time anyway: the weakside linebacker and edge defender both got out clean, the ‘backer shooting to cover the outlet pass and the edge defender pressuring Rodgers.

Rodgers was forced to deliver a nothing ball while moving backward. He didn’t have time set up to check the wheel. And because the Saints started in a split safety look, they were able to take away the intermediate over route.

There are no perfect answers. Wherever you try to take something away, you open up a new stress point. The Saints were able to limit what the Packers wanted to do because they could live in two-high sets – erasing any early snap mistakes – and because the threat of the run was not a real, genuine thing given the flow of the game – the Packers were already in a two-score hole.

Still: Quarters is the only decent coverage answer.

The Lions were lit up in the boot game in week one against the Niners by playing single-high, man-free coverage. It was prototypical boot stuff; the Lions tried to match the Niners big-bodied personnel groups to shut down the run and were left zigzagging across the field trying, in vain, to locate George Kittle.

Against the Packers in week two, Lions DC Aaron Glenn tried to replicate Dennis Allen’s plan against Green Bay in week one. Glenn wants to play in a two-man shell. He coached with Allen in New Orleans before coming across to Detroit. That’s who he is.

If they can force you out of that two-high shell, where can’t bracket the intermediate guy, you’re in trouble. On Monday night against the Packers, Detroit tried to stick in two-deep looks down in and down out, no matter that the Packers were mashing them upfront.

That didn’t work, either. The Lions remained committed to playing run first, just with a better-looking shell behind. They busted against keepers by sticking to the shuffle-shuffle-shuffle backside mantra rather than triggering on the quarterback, who had time and space to make easy throws:

It’s a philosophical decision. Some coaches are cool with restricting themselves versus the run if it can take away shot plays via the boot. Others cannot shake the habit of a lifetime. They want to match the run and take their chances with coverage on the backside.

But greenlighting the quarterback has already proven to be effective.

Is it a long-term solution?

“From what I’ve seen, the best way to defend boot is to have a designated quarterback player on the d-line,” Cody Alexander, the author of Match Quarters told The Read Optional. “I think that is what most are going to start doing; building a defense back to front. The key is really the backside DE attacking the quarterback. The issue can be the backdoor cut. If he gets too vertical, the RB can cut and roll out the backdoor. It’s hard, but good running backs can find a way.”

So far, non-Detroit coaches have been willing to take that gamble.

The horizontal-stretch brigade will try to find answers of their own to this defensive remedy. In fact, you can dig into the boot-actions immediate past to see how this thing might unfold moving forward. In the early McVay years, the Rams ran some boot-action stuff but not to the same degree as they did in the final Goff year. They ran straight-back play-action, so to speak. Turn. Fake. Fire.

The first team to really make the McVay machine stall out in 2017 was Pete Carroll’s Seahawks side, the team that – schematically speaking – was the reason McVay had structured his offense in the way he had in the first place.

Sure, Seattle still had all those future Hall of Famers strolling around the field. And that was a massive part of the team’s success in holding the Rams to ten points; they were able to play in man-coverage and stay so in-sync that designs that ripped other teams apart had no impact on the best to ever do it. But Carroll added his own special bit of je ne sais quoi, in a way only Carroll could.

The Rams lined up in their typical condensed formations, compressing the field pre-snap so that they could run into space post-snap. Seattle knew the deal: Goff was either handing the ball off or faking it and throwing it. To disrupt the timing of pass patterns, Carroll had his edge defender body the Rams’ slot receiver at the snap before he got into his run fit or pass-rush:

It caused an unfavorable delay for the Seahawks against the run, but it took away Jared Goff’s go-to guy in the quick passing game. Once the Rams were stuck in third-and-long, it was game over.

McVay adjusted. Now came all the boots and the pocket movement, all to buy a little more time, to give his receivers a chance to get back on schedule if they were disrupted at the line of scrimmage. He started to keep extra bodies in to protect, too.

Now, the Rams will regularly run boot with only two-man route combinations, with one receiver – a back or tight end – slipping out of the back door late in the play if things are sealed off downfield.

It’s a tactic that has spread throughout the league:

If defenses are going to continue to trigger on the quarterback, then offenses are going to keep extra players in to wall off the backside of the first level rather than charging up to the second-level.

That’s still a win for the defense, really. Without players firing up to take-on linebackers, the offense isn’t really selling the run-part of the run-action, nor do they have the combination intermediate-under route that puts the linebackers in conflict.

Sticking in a two-deep (cover-4 or cover-6) offers numbers against the deep passing progression, too; the very fear that the edge defender will exclusively play the quarterback can stymie some of what the offense wants to do in its vertical passing game.

McVay, Shanahan, LaFleur, Stefanski, et al. committed to the boot-action life. Defenses — the smart ones, at least — have adapted. Now it’s over to the horizontal-stretch guys to find fresh answers.

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