What's In A Scheme? The 3-4 defense

For the second time in two years the New York Giants are looking for a new coordinator after a horrid season. As we all know, last year it was on the offensive side of the ball following the retirement of Kevin Gilbride. This year, the Giants find themselves looking for a new defensive coordinator.

It initially appeared as though Perry Fewell would be returning to the Giants' sidelines in 2015, but in a surprise announcement early on Jan. 7, the Giants and Perry Fewell quietly parted ways.

And with that the Giants' off-season was suddenly in an entirely new light.

A year ago, Giants' fans agonized and argued for nearly two weeks over who the best candidate to fix the broken offense was, and what offensive system would fit Eli Manning the best. The decision was ultimately made to hire Green Bay Packers' quarterbacks' coach Ben McAdoo, and what resulted was one of the most interesting off seasons in recent memory.

What made it so interesting was that after watching Gilbride's rigid and largely predictable offense for years, fans had no clue what to expect out of the system or the players brought in to remake the offense.

It looks like Giants' fans are in for another off-season of not knowing what to expect in free agency or the draft, so let's take a look at what the various schemes could entail as the Giants remake and reinvigorate their defense.

3-4 Schemes

2-Gap 3-4

For the most part, there are two types of 3-4 defensive fronts: One-gap or two-gap.

The base, old school 3-4 defensive scheme was developed by Bud Wilkinson at Oklahoma in the 1940s. It is a two-gap scheme, meaning the three down linemen are primarily responsible for occupying the offensive line to free the linebackers to make plays. It's called a "2-Gap" system because each of the linemen are responsible for two gaps in the offense.

In this scheme, the nose tackle (N) plays the 0-technique, lining up directly over the center. He is responsible for the "A" gaps on between the center and the two guards. The defensive ends (E) play the 5-technique, lining up directly over the left and right tackles, and are responsible for the "B" and "C" gaps to the inside and outside of the tackles, respectively.

The inside linebackers come up to meet the guards and help the defensive linemen make stops between the tackles, while the outside linebackers get to attack down hill, or cover the tight end or running back.

As of now, the Giants don't really have the personnel to run a 2-gap 3-4 defense. Johnathan Hankins is the natural fit as the nose tackle, while Jay Bromley could fit as one of the ends. Jon Beason and Jameel McClain could probably fit as the inside linebackers while Mark Herzlich and Devon Kennard could fit as outside linebackers.

And that's all well and good. However, there are some significant problems. First, three of the defense's best players don't have a fit. Jason Pierre-Paul -- assuming he is re-signed -- and Robert Ayers would be relegated to soaking up blocks, largely wasting their talents as disruptive pass rushers. They are also very undersized for traditional 2-gap 34 defensive ends. While Ayers and JPP generally play around 270 pounds, 3-4 defensive ends normally play at 300 pounds or more.

Meanwhile Damontre Moore could find himself in a positional no-man's land as he has worked to finish adapting his body to being a 4-3 defensive end. He would be too small and weak to play defensive end in a 3-4, but too big to be an effective linebacker.

The other problem is depth. The Giants don't have a back-up for Hankins at NT. That's a problem anyway, but it is magnified in the 2-Gap 3-4. In that defense the NT is arguably the most important player. As a big, high-effort tackle, Hankins wears down quickly if he plays too many snaps. Without an effective back-up, Hankins would tire and the defense could crumble. Likewise, the Giants would be thin in both talent and bodies at linebacker.

All in all, the base 2-Gap 3-4 defense isn't a good fit for the Giants without some major remodeling in the defensive personnel

One Gap 3-4

The other main variation of the 3-4 in use in the NFL is the one gap 3-4. Predictably, this scheme calls for the defensive line to only be responsible for a single gap rather than two. As a result, this scheme is more aggressive than the 2-gap 3-4.

Once again, the one-gap 3-4 is built around the nose tackle (N). However, what dictates that this is a 1 gap scheme is the NT attacking a single 'A' gap. That dictates to the offense where the double team will be. By directly threatening a gap with a tackle who has to be double teamed, it dictates the offense's blocking scheme. By dictating the blocking scheme, the defense is able to create a numbers advantage. In the diagram above, there is a 4 on 4 match-up on the right side of the offensive line. However, the center and right guard should have to double team the nose tackle, creating a 4 on 3 advantage for the defense. On the left side of the offensive line there is a 3 on 2 advantage for the defense.

All of that means that there should be two defenders unaccounted for along the line of scrimmage.

Because the defensive line isn't occupying blockers, but attacking gaps and attacking upfield, it uses smaller players than the 2-gap 3-4. Hankins would still be the obvious choice for the nose tackle, but Jay Bromley could effectively back him up or play strong side defensive end.

Jason Pierre-Paul, Robert Ayers, and Kerry Wynn all have enough size and strength to be a defensive end in a 1-gap 3-4. They are still smaller than ideal -- even in a 1-gap 3-4, the 5-techniques still weigh in at roughly 290 pounds -- but they can put their greater athleticism to use getting into the backfield.

Likewise Damontre Moore could play the "Elephant" linebacker position. The Elephant is something of a hybrid linebacker/defensive end position. It is the position played by DeMarcus Ware in Dallas and Aldon Smith in San Francisco. If both outside linebackers are playing close to the line of scrimmage and attacking down hill, the 3-4 defense effectively becomes a 5-2 defense.

Final Thoughts

The 3-4 defense is interesting, and poses some serious threats to offenses. The 2-gap 3-4 naturally lends itself to deceptive scheming. With just three linemen occupying the five offensive linemen, it leaves the linebackers able to move freely. That allows the defensive coordinator to be able to send pressure from anywhere on the defensive formation, or effectively play coverage underneath. It also has some vulnerabilities. Offenses can give the 2-gap 3-4 problems by creating additional gaps and interfering with the front seven's responsibilities.

The 1-gap 3-4 is much more like the defenses the Giants have run recently. The size requirements are closer to what the Giants currently have on their defensive line, and it would allow them to play to their strengths and attack gaps.

The Giants probably still don't have the personnel to make the either variation of the 3-4 their base defense, at least not without some significant personnel overhauling. But, they could use the 1-gap variation as a sub-package to give offenses a different look.

Next time we'll be taking a look at the 4-3 defense, and how a different defensive coordinator could change the way the Giants have done it in the last five years.