One of the more interesting stats about the Pittsburgh Steelers defense is that they do not give up a lot of big plays over the course of a season. That was one of the more shocking things about the playoff loss to Denver two seasons ago.

Anyways, more often than not, the Steelers do not give up big running or pass plays. For the 2012 season, Pittsburgh was tied for the lead in the NFL in yards per play. On average, the defense only gave up 4.6 yards per play. Moreover, according to Cold Hard Football Facts, the Steelers were tied for second in the NFL in the category of yards per pass attempt.

The reason that I think that this stat is interesting is because every year we hear about how difficult it is to learn the defense. We also here about how voluminous the Steeler defensive playbook is. One would seem to think that with a playbook that big, and a defense that complex, they would blow a coverage every now and then.

We see it happen every week in the NFL: blown coverages and busted assignments. Thankfully, these seem to be rare occurrences with the Steeler defense and that is no accident. It is a direct result of how Coach Dick Lebeau installs and teaches the defense.

The Zone Blitz

A lot of ink has been spilled over the years concerning Lebeau's creation of the zone blitz concept. Essentially, Lebeau wanted a way to blitz the quarterback but still play safe coverage (zone) behind the blitz. Oftentimes, when teams blitzed, they played man behind the stunt. The reason why teams played man was that the offense can send out, at the most, five receivers. The defense can match that with five defensive backs, 4 defensive linemen, and two linebackers. The five defensive backs cover the five receivers, and the two linebackers can blitz. The offense only has five people to block, the defense can bring six people, and good things happen.

That is a simple explanation, but you get the idea. You have people (linebackers in the example) not covering anyone, so they can just blitz. In zone coverage, everyone has a zone. In order to defend the entire width and depth of the field, all seven defenders need to have a zone. Therefore, if you blitz one, or maybe two of them, you are going to have huge holes in your defense.

To avoid this, teams play man behind a stunt. The problem with man is that a five yard hitch route can turn into a long touchdown if a defensive back misses a tackle. If you are playing man, your eyes had better be on your man because when a tackle is missed, the other defenders cannot rally and help as quickly. When you play zone, the defenders are all watching the play develop. Therefore, when the defender misses the tackle on the hitch, the other defenders can rally to the ball.

Lebeau's genius was to figure out how to not vacate the zone areas when someone blitzed. The example that most people are familiar with is when the person assigned to defend the flat blitzes instead, and a defensive end drops to cover that zone. That's a simple concept, but you get the idea.

Teaching the zone blitz

So as you can see, playing zone behind a blitz is much safer than man. However, if the person who is supposed to be defending the deep middle 1/3 thinks he is defending the intermediate hook/curl zone, big plays are going to result.

Lebeau is able to avoid this confusion by installing the zone blitzes differently than most coaches. Lebeau always starts with the secondary. Let's say that Lebeau wants to bring Ike Taylor off of the edge on a corner stunt. He'll name the stunt (let's use "Comet" for our example) and then go over the responsibilities in the secondary. Instead of Troy Polamalu having the intermediate zone, he'll drop deep. The outside linebacker on that side will then cover Polamalu's intermediate zone. That is how the Comet stunt is installed from day one.

At this point, Lebeau lets the assistants tinker with the stunt. In one game, maybe the Nose Tackle and the Defensive end do a twist. Maybe during the next game, the defensive line slants away from the blitzing corner. To the offense, these are two completely different stunts that have to be defended two different ways (complexity). However, to the secondary, it is the exact same blitz that was installed during the first day of camp -- Comet.

Other coaches might teach it this way, but Lebeau is the only one that I know off. Most coaches teach their zone blitzes the opposite way: teach the stunt first and then the coverage. I would argue that Lebeau's way is vastly superior and the stats prove it.

With all of that in mind, where does the complexity come in?

Is the playbook really that big?

The answer is yes, and for good reason. The defense is full of veterans that have played in this defense for a long time. They know what they are doing. All playbooks in the NFL are big. Coaches want to have everything in there so that they have every possible situation covered. However, just because it is in the playbook, it does not mean that you are going to run it.

Here is the difference with the Steelers - Lebeau has said on many occasions that the part he still enjoys the most are the in-game adjustments. With a defense full off veterans, you can make adjustments and run things that you may not have practiced that week or even that year. Veterans give you that flexibility. If the Steeler defense was not full of veterans, the size of the playbook would not change; however, what was given to the players would change dramatically.

It is very difficult to make the types of in-game adjustments described previously with a Jarvis Jones or a Shamarko Thomas. How the Steelers avoid this is by doing exactly what they did with players like LaMarr Woodley - create a package of plays that they are comfortable with, and let them run those plays. As the season progresses, you can expand the package.

I do see Jones and Thomas having one advantage, however. Veterans can also be coaches on the field. Larry Foote, Ryan Clark, and Troy probably know the defense as well as Lebeau does. It is not out of the realm of possibilities to think that they couldn't place the rookies in the right spot and communicate to them the correct responsibility for them.

That's a big risk though. As Mike Tomlin likes to point out, you have to see how guys are going to perform in stadiums when the lights come on. You never know until it happens. And if it doesn't happen correctly, it can be six points for the other team.