Fat Camp: Defensive fronts, Part I

A friend and I got to talking recently about 3-4 and 4-3 formations and systems, and I was a bit surprised when he noted, quite honestly, that he really didn’t know much about the differences between the fronts and how they work. After asking around a bit, I found that my friend was far from alone in that regard.  It got me looking at the issue, and what better way to address it than a session or two at Fat Camp? 

Regarding the differences between variations of the 3-4 and 4-3, new Broncos defensive coordinator Dennis Allen takes much the same public stance as head coach John Fox does. In speaking with Dave Krieger of the Denver Post, Allen said,

"I don't look at it as a huge issue. Each player has a unique skill set and the challenge for a coach is to find out what those guys do well. So we're going to give them opportunities to do the things that they do well, whether it's 4-3, 3-4, 4-4, it doesn't really matter. I think our challenge is finding out what our personnel can do and highlighting those strengths."

While this is a good perspective to start with, the predominant thought around Broncos Country is that Fox will be engineering a change back to the 4-3 over the next couple of seasons, but that he and Allen will run a hybrid defense to take advantage of the strengths that the Broncos already have. Under the watch of Mike Nolan in 2009 and then Wink Martindale in 2010, Denver has been a 3-4/5-2 defense for the past couple seasons (Bob Slowik sort of experimented with each front at different points in 2008). The fact that each required different kinds of players (or a very innovative coach) did not seem to enter into the equation for reasons that are probably best not thought about.

So saying, I thought that I’d put together a fairly straightforward discussion of the basics of each approach. For many readers, this will be simply a basic review. For others, it may help establish some level of sense regarding what’s been happening with the Denver defense over the past few seasons. As the team has proven over the past five-plus years, you can stink up any of the options. You can play any of them well, too, and with that in mind let’s get into the basics of the various systems. We’ll take on the 3-4 variants today and handle the 4-3 in our next installment of Fat Camp.

The 3-4 Systems

The Fairbanks-Bullough

It's really not all that complicated - there are two essential forms of the 3-4; or three, if you count the 5-2 separately. I generally don't, but did for this article. One version is that which Denver had tried to move to, the Bullough or Fairbanks-Bullough, depending mostly upon what part of the country you're from. Hank Bullough was the head coach of the Buffalo Bills back in the 1970s, and was a major innovator in defensive strategy, while Chuck Fairbanks was the head coach of the New England Patriots during the same period and installed a similar system there. In fact, Bill Belichick noted in a 2007 press conference,

I think Chuck has had a tremendous influence on the league as well as this organization in terms of nomenclature and terminology and those kinds of things. I'm sure Chuck could walk in and look at our playbook and probably 80 percent of the plays are the same terminology that he used - whether it be formations or coverages or pass protections. We were sitting there talking yesterday and he was saying, 'How much 60 protection are you guys using? How much 80 are you using?' All of the stuff that was really the fundamentals of his system are still in place here even, again, to the way we call formations and plays and coverages and some of our individual calls within a call, a certain adjustment or things that Red (Miller) and Hank (Bullough) and Ron (Erhardt) and those guys used when they were here.

This approach is generally a two-gap system, which means that within this system, each of the defensive linemen have to decide at the snap between two gap options. It will prefer larger, stronger linebackers and it needs the three defensive linemen to try and take up two offensive linemen each; they don't have a lot of responsibilities beyond that, although you always want your DL to stop the runner and/or penetrate if possible. Commanding a double-team from the offensive blockers is often plenty and it should let the LBs shoot the gaps and penetrate, in theory. Not surprisingly, the talent of the LBs is usually considered an essential position for this system.

The Phillips 3-4

The second basic variation is the Phillips (named for Bum Phillips, Wade's father); it's a single-gap version, in which the defensive linemen emphasize penetration. It tends to go with (usually, but it's a matter of coach's preference) slightly smaller, faster LBs who have better coverage skills. Some sources even call that body type a 'coverage LB’, for the same reason. The key to the Phillips 3-4 is quick penetration, whether to harass the QB or catch the running back in negative territory. That's why Dallas has generally done fine with Jay Ratliff as a 305-pound nose tackle - his job is mostly to penetrate, and he doesn't have to weigh 350 to do that. In fact, it can be a disadvantage to have guys that large unless they are blessed with great feet, which is of course an exceptionally rare combination. 

The 5-2

Denver has been running this older variation on the 3-4 for the past two years, but they aren’t alone. I’ve watched the same essential formations (and defensive back approaches) from Pittsburgh, Baltimore and KC, among others. 

The theory behind a 5-2 defense is simple - to draw a balance between having a strong line and keeping a strong defensive backfield. Its advantage is that it takes the versatility that defines the essential 3-4 concepts and uses them in a way that increases the strength of the formation against the run (power running up the middle is commonly considered the more effective way to attack the 3-4) while protecting the defensive secondary.

I found this simple article that offered eight basic steps to establishing this defense. It’s quite rudimentary, as you’d expect, but it covers the alignments that are necessary to setting up this defense. First off, it’s a balanced line. The nose guard is over the center, the tackles (we often call the players just outside the nose guard DEs, but nose guard and DT are more accurate in this case) are generally head-up against the opposing tackles and the OLB/DEs are set up, with one against the tight end and one who may be unmirrored unless the offense is running a two-TE set.

The cornerbacks are placed about seven yards off the receivers, and the strong safety is usually about three yards from the line of scrimmage. The free safety traditionally plays about 15 yards back and is responsible for whatever gets past the linebackers.

That isn’t to say that this can’t be adapted and still run as a 5-2 - it’s a flexible system, and you can move the DL players to different gap or technique responsibilities. What’s listed here is just the simplest way to run it - the basics.

The Zone Blitz

Within any of the above systems and/or formations,  whether a team runs a 4-3, 3-4 or 5-2, they might utilize zone blitz concepts. This is typified (or optimized, more appropriately) by Dick LeBeau from Pittsburgh, so you can see it in any Steelers game, including this year’s Super Bowl; Green Bay defensive coordinator Dom Capers is also refining and upgrading it (Please see Chris Brown's fine article over at SmartFootball.com for a look at LeBeau and Capers' work in perfecting the zone blitz). Almost any formation or system can and usually does use it at times during a game. Most sources state that LeBeau invented the zone blitz when he was in Cincinnati, while other sources have suggested that it was around in some form back in the 1970s, at the latest. Bill Arnsparger used a version of it in Miami that he called ‘safe pressure’ back in 1971. Certainly, Chicago used similar principles in their famed 46 defense under Buddy Ryan's direction.  But nobody questions that LeBeau maximized its usefulness while the defensive coordinator at Pittsburgh in the 1990s and over the past decade: he’s already in the HOF as a player, and he almost certainly will be added as a coach. Since the NFL is a copycat league, it’s no surprise that the use of the ZB in some degree has turned up on nearly every team.

The key to the zone blitz is to bring up your players in a normal formation (relative to your default scheme), but to then rush one or two fewer DL players and bring more LBs (or safeties and/or CBs) while the DL player(s) drop into coverage. Matt Bowen of the National Football Post and Tim Layden in his book Blood, Sweat & Chalk both write that it’s specifically about rushing 5 players and dropping 6 back. The zone blitz is a great and rare example of playing defensive aggressively and yet safely - hence Arnsparger’s term, safe pressure.  That’s one thing that really has drawn me to this system - that, and its remarkable effectiveness.

The advantage comes from the offense not knowing where the pressure will come from. You may recall that Denver's own Marcus Thomas intercepted a pass by dropping into coverage back when Bob Slowik experimented with the zone blitz for a good five minutes back in 2008 - Bucs QB Jeff Garcia discounted him as a pass defender and threw the ball right to Thomas. The same thing happened with B.J. Raji of Green Bay in the most recent NFC Championship game against Chicago, and the touchdown he scored with that interception ended up constituting the Packers' winning margin. Linemen drop off, other positions attack unexpectedly, and it can drive QBs and OCs insane.

The late, legendary Philly defensive coordinator Jim Johnson was a genius at adapting the ZB, along with many other options, out of a 4-3 look. Johnson possessed an astounding ability to create new and more effective blitzes, stunts and twists on the spur of the moment that took away the strengths of opposing offenses. The Eagles' loss of Johnson to cancer in 2009 was a huge blow to the team, emotionally as well as in terms of their defensive playcalling. His use of the zone blitz, among other approaches, was remarkable in its versatility and effectiveness, and his contributions to the sport and to the NFL will surely stand for many years to come. 

Players and Nomenclature

As I’ve noted, the center player on the defensive line of any of the 3-4 variations is more properly referred to as a nose guard, rather than the more popular ‘nose tackle’, which is really a position on the 4-3 line. The player next to the nose guard is going to be a DE or a DT depending on whether you’re running a ‘true’ 3-4 or a 5-2 (on many teams, and Pittsburgh is a great example of this, you’ll see both in any given game). In addition to that, the use of the term ‘5-technique DE’ or just ‘5 technique’ has become vastly and inaccurately overused when referring to the players next to the nose guard. Those players, who may be referred to as DEs or DTs, depending on the precise system that’s being run, are much more than a ‘5 tech’.

The term technique refers to the location where these players will align in a normal play. The term is used instead of the common ‘gap’ lettering - the A gaps are between the offensive center and guard, the B gaps between the guard and the offensive tackle and so forth. The change to the term ‘technique’ was an attempt to more precisely align the defensive players.

The term itself is often credited back to Bear Bryant, but that’s incorrect. Actually, it’s the invention of Bum Phillips, who also developed the Phillips 3-4 system discussed above. Bryant himself noted this on page 29 of his book Building a Championship Football Team.  I pulled up this article which deals with the issues of just what the terms ‘gap’ and ‘technique’ actually refer to, since it seems that many commentators themselves don’t know. From it, you can see that the term ‘5 technique’ refers to a player who lines up directly across from the outside shoulder of the offensive tackle, permitting him access to the B and C gaps. That’s great, but it’s not what all 3-4 DE/DTs do. It’s also worth noting that the placement of the generally accepted ‘technique’ terms have evolved from where Phillips left off. He didn’t even use the term ‘4 technique’, and his original placement of the 3 technique was in the middle of the B gap. That’s all changed.

In different formations, you’ll see a 3-4 DT lining up as a 3 technique - across from the outside shoulder of the offensive guard - or even the 1 technique, which is across from the shoulder of the center, if originally  in the middle of the A gap. You’ll find that while the ‘gap’ lettering is generally simple, accurate and accepted, Bum had gone to the numbering of placements because he wanted his players to be precise in where they line up, and to number the shoulders of the OL made more sense to him. In his early phase of this, some terms were more nebulous, but things have settled now. You’ll still run into discussions, usually at the high school level,  that argue whether the 1 technique is the center’s shoulder, with a 0 technique being directly across from the center, or whether the 1 technique is across from the guard’s inside shoulder.

In the NFL, the 1 technique is across from the center’s shoulder, and the zero technique would be directly on the center’s helmet. Confused? Don’t be. There’s a nice chart right here to straighten you out if anything is still not clicking for you.

Keep something in mind:  We’ll be covering under and over formations in next Wednesday's edition of Fat Camp. When an NFL coach is using the 3-4 and makes over/under changes (and they do), a DE/DT might line up anywhere from the 0 technique to the 5 technique. Don’t let anyone tell you differently. The people who love to toss out the term ‘5 technique’ to describe the 3-4 DE/DT are just being intellectually lazy. It’s easier than dealing with the intricacies of modern defensive alignments, but it’s not accurate, all the same.


Those fans and coaches who prefer the 3-4 defense usually consider it to be more flexible than the 4-3. That’s a matter of opinion, and opinions, as always, vary. Many coaches, and John Fox has been among them, downplay the differences.

John Elway noted, "John has coached the 3-4 and the 4-3 (defenses), and he wants to see what system here best fits the personnel.” While it’s generally thought of as hard to argue that different personnel are required for either system, Fox’s perspective on that question is interesting:

Not really. It’s semantics. Obviously there are some personnel things that aren’t that deep-seated. Everybody plays under/over, whether you originate out of the 3-4 or 4-3. A lot of it is pretty much the same.

During his introductory press conference on January 14, Fox told the assembed media,

There is no doubt that right now, the Broncos defense has been structured to a 3-4. I have been doing this for a long time and have a 3-4 background as far back as 1989 with the Pittsburgh Steelers. That is something that will be fluid going forward, too. Because regardless of the spacing and the terminology of the positions — whether it be nose tackle, weak inside linebacker, weak outside linebacker — you still have the spacings and everybody utilizes pretty much all the same spacings. And, you can get to that either through the 4-3 or the 3-4.
Fox’s own history in defense was at its peak when he had a 4-3 formation in Carolina with powerful players on the defense, with many on the defensive line. LB Jon Beason, DT Kris Jenkins, and DE Mike Rucker are each examples of the level of players that Fox has coached successfully on defense. Clearly, Denver is currently missing that kind of quality on the defensive front (they have some good rotational players), although players like Justin Bannan and Robert Ayers may take the next step under Fox and defensive coordinator Dennis Allen, who coached the secondary for the New Orleans Saints in their Super Bowl-winning 4-3 defense. It’s not a secret that Denver fans can look for the draft to be heavy on defense.

While Fox hasn’t been specific on this, it’s almost certain that he’s looking at the players with an eye towards both upgrading the personnel and transitioning to a 4-3 defensive front. With that being the case, our next installment will deal with the 4-3, and some of the ways that Fox could choose to use it. I’ll see you next week!

Learn to laugh at yourself. You will be ceaselessly amused. - Sri Gary Olsen

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