For the next month or so, as a lead-up to training camp, I’m doing a “Steelers Playbook” series that focuses on some of the schemes the team most commonly uses. Today, we take a broad look at their base defensive system, the 3-4 front.

In 1982, the Pittsburgh Steelers became the first NFL team to switch to a 3-4 defense as their primary front. The 3-4 had not been very popular to that point because it replaced a defensive lineman with a linebacker in the front seven. Offenses were run-heavy at that time, and the conventional wisdom suggested you stopped the run by putting gap-clogging linemen up front with tackling machines at linebacker behind them. The 4-3 and its predecessor, the 5-2, did just that, and were the base fronts played by every NFL team up through the 1970s. The 3-4 was thought to be a situational defense a team could employ in passing situations, but little more.

Pittsburgh changed that line of thinking. The change is often attributed to then-head coach Chuck Noll, but it was actually his linebackers coach, Woody Widenhofer, who encouraged the move. By the early 1980s, Widenhofer understood that NFL offenses were leaning more heavily on the passing game, and that this trend was likely to continue. The Steelers had seen the heart of their once-great defensive line – Joe Greene, L.C. Greenwood and Dwight White – all retire by then, but they still had quality linebackers in Jack Lambert, Jack Ham and Robin Cole, and a capable backup in veteran Lauren Toews. Rather than replace their entire front, Widenhofer suggested the Steelers plug Toews into the lineup and switch to the 3-4. The scheme would compliment Pittsburgh’s available talent as well as address changes in the way the game was being played on offense. Two birds, one stone.

Forty-two years later, the team is yet to switch back.

That last sentence comes with a caveat. It would be disingenuous to suggest the Steelers are a base 3-4 in anything more than name these days. Given the complexity of offenses in the 2020s, their use of smaller personnel groupings and the emphasis on both speed and passing, the Steelers play that base on less than 40% of their defensive snaps. Most of their reps now come in sub packages that replace at least one defensive lineman with a defensive back. The last several years, the 2-4-5 nickel has been more of a true base for the Steelers than the 3-4.

Still, Pittsburgh identifies as a base 3-4 team. What exactly does that mean? Let’s do a primer and explain how it works.

Most readers understand the fundamentals of Pittsburgh’s base 3-4: the Steelers use three down linemen, four linebackers and four secondary players. The linemen tend to be big and strong, capable of handling double teams and holding gaps; the linebackers are athletic and versatile, can stop the run, rush the passer and play in coverage; and the secondary plays multiple coverage schemes and requires tough players who are willing to tackle. That’s been the nature of the defense for decades.

Beneath that broad outline, the 3-4 is an intricate and complex scheme. Our interest here is in the front seven, so that will be our focus. I’ll address the secondary in a separate article. Generally-speaking, the Steelers play their linemen in head-up techniques where they are aligned over top of an opposing blocker. The nose is on the head of the center and the defensive ends are head up on the offensive tackles. The reason they like these alignments is because it gives them the ability to slant in either direction as opposed to simply plugging the gap into which they’ve aligned.

The Steelers will slide their front to “shade” techniques at times, meaning they will bump to the shoulder of an offensive lineman. When you hear a player referred to as a “1-tech” or a “3-tech,” this means they’re in a shade alignment. For more on how shades work, check out the Twitter link below:

One of the most common questions I’m asked as a football coach is how to understand the defensive line numbering system? It is an essential part of properly setting up a defense, so players are where they’re supposed to be and something that is extremely beneficial for both… pic.twitter.com/lBY3vJvki1

— The Coach’s Call Sheet w/KT Smith (@CoachsCallSheet) June 3, 2024

In a typical 3-4, the defense lines up as follows against an attached set from the offense, meaning a formation that uses a traditional tight end:

The Sam backer in that graphic is often T.J. Watt while the Jack is Alex Highsmith. When there is no tight end, the Steelers roll with a sub-package defense. The base 3-4, then, is only meant for bigger personnel groupings from the offense.

As far as run fits go, these vary by assignment. A “fit” is the gap a defender is responsible for in the run game. These are fluid, meaning the fit can change as the play evolves, but all plays begin with defenders assigned a particular gap. In the base alignment shown above, the nose would have both A-gaps (thus the phrase “two-gapping”), the ends would pinch into the B-gaps between the guards and tackles and the Sam and Jack would “cage”. Cage means they will squeeze the edge and force the ball to turn up inside of them. The Mike and Will backers, which in Pittsburgh terminology are the Buck and the Mack, would play inside-out from the A to the C gaps.

A run into the strong B-gap, for example, would be met by the end caging and the Mike backer playing over the top looking for the ball to bleed into the C-gap. The Will backer would scrape from the back side, closing off any cutback into the A-gaps. The strong safety would fit into the play-side alley, while the free safety would back-fill for the linebackers. The back-side corner would take a “save man” angle in case the run broke loose:

A defense can get creative with these fits by running “gap-exchange” stunts where two defenders switch responsibilities at the snap, or by slanting the entire line. In the image below, the defensive line stunts towards the strong side with the Jack backer executing a “spill” technique. This means he is coming down hard into the B-gap to force any run his way to bounce outside. Meanwhile, the Will backer plays over the top into the alley, where he is unblocked:

The idea of spilling a play like this is to force the running back into a defender who cannot be blocked. Here, the movement of the front washes down the offensive linemen, keeping them from climbing to the inside backers. The Steelers run these types of stunts commonly. As a result, they have moved away from two-gapping space eaters like Casey Hampton up front and are now drafting players like Keeanu Benton who can move and penetrate. Meanwhile, the addition of athletic linebacker Patrick Queen means they could get even more aggressive in 2024.

The 3-4 isn’t much different in its run fits than any other front. Each gap has a player to which it’s assigned, and “gap integrity,” or the manner in which all gaps are filled, is key to successful execution. But, in utilizing an extra linebacker instead of a defensive lineman, the 3-4 is more flexible than its predecessors and can give a coordinator more options in terms of stunts, coverages and disguises. It’s been the base of the Steelers for over forty years because it’s the best answer, personnel-wise, to how modern offenses operate.

For my video breakdown on how the Steelers fit the run in their base 3-4, check out this video from our SCN YouTube channel in the player below: