Overview of the 3-4 Defense

[FLCowboyFan]

Since it seems that many people here mix up defences (e.g. what is the difference between a 3-4 and a nickle package) I thought I would add a bit of knowledge to the board (plus I found a cool reference )

reference: http://football.calsci.com/DefensiveLine3.html

The 3-4 Defense

The Basic 3-4 Defensive Alignment

Another popular defensive alignment is the 3-4. This defense was used by Bill Parcels and his N.Y.Giants to win a couple of superbowls. From 2000 to 2004 it was also used by Bill Parcels' former defensive coordinator and now head coach of the New England Patriots, Bill Belichick, to win three more superbowls. This defense is now becoming quite popular again. The NFL is very much a copy-cat league.

In the 4-3 defense, you need two very large and athletic defensive tackles and two somewhat large and very athletic defensive ends. These guys are very hard to find. It seems there's about one excellent defensive end prospect in each draft, which is not nearly enough to go around. If you can't find a couple of good defensive ends, you're in for a long season of living and dying by the blitz.

One reaction to this has been to develop the 3-4 defense. In this defense, you need one really large nose tackle. This NT has to be a real monster of a guy, 350 pounds or so, because his job is to take on the center and one of the guards simultaneously on every single play. Then you get two more defensive tackles at around 300 pounds each, and play them up against the offensive tackles. All three of the defensive tackles have what is called two-gap responsibility. They are expected to hit the offensive linemen head on, and watch the play to make sure the running back doesn't come through on either side of them. Also, they're expected to hold their block so that the offensive linemen can't get out and block a linebacker.

In the 3-4 system, the linebackers are expected to make most of the plays. In the 3-4 system, the DTs play a more physical game as they are taking on one or two offensive linemen directly, play after play. Unlike the DTs in the 4-3, the DTs in the 3-4 are responsible for every single gap in the offensive line. Although the DTs get relatively few chances to make tackles or sack the quarterback, anything bad that happens is still ultimately their fault.

In the 3-4, you have four linebackers. Two of these guys are inside linebackers, and are expected to weigh roughly 240 pounds and be quite athletic. You also have two outside linebackers. These guys are sometimes called "tweeners," as they are in between the normal size of defensive ends and linebackers. These guys should weigh perhaps 255-265 pounds and also be quite athletic. Because these are linebackers, they tend to be faster than the heavier defensive ends. Their presence makes it much more difficult for the quarterback to roll out, as he will be rolling out directly into the path of one of these linebackers.

In the NFL there are many running backs who are incredibly athletic. O.J.Simpson was perhaps the first of these, but today there are perhaps a dozen of them. These guys are very shifty and hard to chase down. Defensive linemen simply can't do it. So the solution was to remove one of the DL from the defense and substitute a fourth linebacker. These linebackers have the speed to chase down such running backs. The 3-4 defense was motivated by two factors: the difficulty in getting good defensive ends, and the need to stop very fast running backs. This is the strength of the 3-4. The DTs keep the offensive linemen off your linebackers, leaving them free to roam the field and bring down runners.

Unfortunately, the 3-4 has a weakness. Three DTs cannot reliably collapse the five offensive lineman pocket on the quarterback, so it becomes much harder to pressure the quarterback. Traditionally, the 3-4 has struggled against the pass. The modern solution to this problem was worked out by Dick LeBeau, and it's called the Zone Blitz. In a normal blitz package, you have five or six guys rushing the passer. The remaining linebackers and defensive backs often played man coverage, which is relatively dangerous. Wide receivers in the NFL tend to be taller than defensive backs, so they often win the one-on-one battles.

In the 3-4, you select your four linebackers for the speed to drop back and cover a zone. Since there are four linebackers, the quarterback cannot guess which one of the four will rush on any given play. Whichever linebacker rushes, it's relatively easy for the other three to shift around a bit and fill in the zones. Sometimes the defense will rush two linebackers on the same side, so there are two defensive tackles and two linebackers attacking three offensive linemen. The remaining two linebackers again can quickly shift over to fill in the gaps left by the two who are blitzing.

If the 3-4 defense finds itself late in a game protecting a lead, there is no need to switch to a prevent defense. Since all four linebackers are skilled in coverage, you can just drop all four of them into zones, playing eight men in zone coverage. It's next to impossible to do this with a 4-3 defense.

The 3-4 defense can have trouble matching up against a very fast offense. It's important for the success of the 3-4 in these cases for the defense to play an extremely physical game, jamming the receivers hard at the line of scrimmage. In the 2002 superbowl, the Patriots looked like their defense matched up poorly with the numerous fast receivers of the Rams, but by playing an intensely physical game the Patriots managed to slow the Rams enough to eke out a win. Similarly, in the 2004 playoffs the Patriots hosted the Colts, and again it looked like a bad match up for the Patriots. But by making the Colts play a more physical game than they were used to, the Patriots managed to almost completely shut down the Colts offense. Had this game been played indoors in Indianapolis on carpet instead of outdoors on grass in cold weather, it's quite plausible the Colts would have found a way to exploit the lack of speed in the Patriots secondary.

So in summary, the more traditional 4-3 offense seems better suited to the modern pass-friendly NFL rules, while the 3-4 offense seems more geared to stop the run based offenses of the 70s and 80s. However, by mixing up the rushers and zone coverages to confuse the quarterback and by forcing the receivers to play a far more physical game than they would wish, the 3-4 has been successful at the highest levels, in spite of it's apparent drawbacks.

 

[Dayton Cowboy]

Very nice find. Its interesting to note that Ellis was able to generate sacks in the 3-4 given that typically the DE or in the case of this reference the DT position aren't generally able to get the sacks on the QB. I'm hoping the Ellis does pick up the OLB position and the ability to work in space.

 

[FLCowboyFan]

Very nice find. Its interesting to note that Ellis was able to generate sacks in the 3-4 given that typically the DE or in the case of this reference the DT position aren't generally able to get the sacks on the QB. I'm hoping the Ellis does pick up the OLB position and the ability to work in space.

It seems to me that as long as he can cover in space that he is perfect size for the position. I also thought it was great that BP was mentioned as the father of the 3-4 (ok, maybe I'm stetching it a bit)

 

[Anguillidae]

Very nice find. Its interesting to note that Ellis was able to generate sacks in the 3-4 given that typically the DE or in the case of this reference the DT position aren't generally able to get the sacks on the QB. I'm hoping the Ellis does pick up the OLB position and the ability to work in space.

Last year Ellis got most of his sacks when the team played in the nickle defense.

 

[junk]

Last year Ellis got most of his sacks when the team played in the nickle defense.

What were they running when he got his sack? For some reason, I thought his hand was on the ground and he came from the left side.

 

[Cowboys&Caps]

they were in Nickle when Ellis got his sack

4 linemen
2 linebackers
3 corners
2 safeties

 

[FLCowboyFan]

Here is more info from the site on the Nickle and Dime packages

Defensive variations

There are many variations on the basic defense outlined so far. We'll look briefly at the most common variations, the nickle and dime packages, the prevent defense, and the 3-4.

The Nickle Package

FS SS
CB ML SL
CB E T T E CB

SE T G C G T TE
SR Q FL

R

Some teams like to pass the ball a lot. If a team has a good quarterback and three very good wide receivers, it would be foolish for them to leave a receiver on the bench just because "normal" football alignments include a fullback. So such a team will frequently take their fullback off the field and substitute a third wide receiver, a slot receiver. This is especially likely if the situation on the field calls for a pass, for example it's third down with 8 yards to go. Few teams would run the ball in this situation.

When a fast wide receiver is put in place for a fullback, there is a mismatch on the field. You might expect that the weak side linebacker would cover the third wide receiver, but there is little chance he can successfully do this. A linebacker is a 245 pound guy who is trained to deliver big hits, and the third wide receiver is most likely a 185 pound guy who runs like the wind. The receiver is going to run right by the linebacker. So the defense will most likely remove the weak side linebacker from the field and substitute a third cornerback. The defense now has three cornerbacks and two safeties on the field, for a total of five defensive backs. Since there are five backs, this is called a nickle package. If you are defending against a passing team like the Rams or the Colts, it is likely that your team will start out the game in their nickle package and never actually play their base defense. Of course it's very important that your team have a quality third cornerback, or you will still have a mismatch on the field and you are still in trouble.

The Dime Package

FS SS
CB ML CB
CB E T T E CB

SE T G C G T TE
SR FL
Q R

There are several running backs in the NFL who are just as accomplished catching the ball as they are running with the ball. In obvious passing situations, many teams will put their running back into motion or split him out as a fourth wide receiver, or in a few cases if the team has four quality wide receivers they might even remove their running back from the game and substitute a fourth wide receiver. In any case, you now have another case where a fast guy, a wide receiver or running back, is being covered by a linebacker. This is again an obvious mismatch, and the defense is in trouble. So the defense will respond by pulling another linebacker off the field and substituting a fourth cornerback. There are now six defensive backs on the field. Just as five defensive backs is called the nickle package, six defensive backs is called a dime package. If your team doesn't have a quality fourth cornerback, you're in trouble.

In the nickle and dime packages, there are few linebackers on the field, so the defense is more vulnerable to a running play. The idea is that if it's third down with eight or more yards to go, the safeties can get up and stop the running back before he gets eight yards. On first down this would be a terrible blow to the defense, to give up seven yards on a running play. But on third down with eight yards to go, giving up seven yards means the defense wins and gets to go sit down.