Wednesday, July 22, 2009

4-3 and 3-4 Defenses, Part Three

by: Matthew Heuett

4-3 Strengths and Weaknesses

To recap, the 4-3 wins by putting more players back in pass protection than older schemes without becoming weaker against the run, and then augmenting the effectiveness of its pass coverage by putting pressure on the passer by collapsing the pocket with the nose guard while the 3-tech, both defensive ends, and the occasional blitzing linebacker rush the quarterback. Having a middle linebacker who can alter the defensive scheme on the fly to better counteract the offense’s plays doesn’t hurt, either.

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However, the success of the 4-3 depends on the pass rush to such an extent that (as we all saw last year) the rest of the defense tends to fall apart if the pressure isn’t getting to the quarterback, and that pressure depends most of all on the defensive ends. Which leads us to the scheme’s main drawback: good 4-3 defensive ends are rarer than red emeralds. There are a lot of teams out there trying to run a 4-3 but there aren’t enough Jason Taylors and Jared Allens to go around, which means that several of those 4-3 teams are trying to make it work with inferior talent manning one of the scheme’s key positions.

For me at least, that bit of information really puts Kerney’s value to the team in perspective. Yes, the guy’s been hurt a lot lately and is on the downward slope of his career, but he also has the ninth most sacks of all active players in the league. What other defensive end on the team is going to replace that level of production? Even if he’s only seventy or eighty percent of the player he once was, he’s still an upgrade over all of Seattle’s other options.

More importantly, if Kerney and his production at DE is lost for the season again, will it matter if the offense and the rest of the defense is better than its 2008 incarnation? Who will replace him after he’s used up the last few seasons left in his tank? There’s no guarantee that another pass-rushing prodigy will show up in the draft or free agency anytime soon, and even if they do, there’s no guarantee that Seattle will be in a position to draft or sign that player.

I’m not saying these things to rain on everyone’s parade -- far from it, actually. I’m just trying to emphasize the main drawback of running a 4-3 defense: a great deal of your team’s defensive success rests in your ability to sign and hold on to a particularly rare and highly sought-after type of player. For that matter, above average 3-techs and nose guards can command pretty high salaries, too (Haynesworth, anyone?). As Wade Phillips put it during an interview conducted during the NFL league meetings back in ’07,
It’s harder to find defensive linemen to play a 4-3 and pay for all of them. In this day and age where salary cap is so important, D-linemen are the highest-paid guys and to get the guys we had in Philadelphia with Reggie White and Jerome Brown and Clyde Simmons, there’s no way you could keep those guys.
Without prime talent on the defensive line, 4-3 teams are forced to augment their pass rush by blitzing linebackers on nearly every down (sound like the ’08 season of any team you know?). This means 5-6 players are being committed to the pass rush, leaving only 5-6 guys in the defensive backfield where there should be seven. No matter how you try to shift coverage to compensate, there will be more opportunities for the offense to exploit, whether through passes to zones the remaining personnel can’t cover effectively, or through draw plays that allow the running back to slide right on by those blitzers into a field that now has fewer tacklers to evade.

So, now that we’ve gotten an idea of the strengths and weaknesses of the 4-3 (and how well Seattle can field the scheme with its current roster), let’s take a look at the other main base defense in the NFL.

The 3-4 Defense

The 3-4 defensive scheme is actually a bit older than the 4-3, having been developed in the 40s by college football hall of fame coach Bud Wilkinson, but it didn’t migrate over to the NFL until the '60s. Once there, it was used by some of the best teams of the era, including the ’72 and ’73 Dolphins under defensive coordinator Bill Arnsparger and the ’69 Chiefs under head coach Hank Stram, but only as a changeup -- each still used the 4-3 as their base defense.

The guy that changed the perception of the 3-4 in the NFL was Chuck Fairbanks, head coach of the Patriots from ’73 to ’78. Using the 3-4 as the team’s base defense, Fairbanks took the Patriots from a perennial sub-.500 team to playoff appearances in ’76 and ’78. Other coaches took notice, and the 3-4 became the base defense of some of the best defenses in the NFL, including the Broncos’ Orange Crush defense of the late ‘70s and the Giants’ Big Blue defense that helped the team win Super Bowls in ’86 and ’90.

As we’ve seen so far, new football defenses were developed largely by pulling more defensive linemen off the line to add players to the defensive backfield, and the 3-4 is no different. It just takes the process one step farther than the 4-3:

In terms of numbers, the difference isn’t that great: three d-linemen and four linebackers for the 3-4 versus four linemen and three linebackers for the 4-3. However, in terms of how the defense operates, that shift of a single player changes things completely for the front seven (the only significant change for the defensive backs is an emphasis on more physical play, so 3-4 cornerbacks are more likely to jam receivers at the line).

Defensive Linemen in the 3-4

Now that the d-line is outnumbered five to three, their priorities have to change -- they simply don’t have enough bodies to pull off any of that one-gap, pressure-and-disruption business that is the heart and soul of the 4-3. Instead, the 3-4 defensive linemen focus on two things: occupying offensive linemen, and keeping an eye on two gaps at once. The nose tackle (basically a specialized name for a nose guard when he plays in a 3-4) lines up directly in front of the center in the 0-tech and watches both A gaps, while the two defensive ends line up nose-to-nose with the tackles (although depending on the play the DEs may line up in the 4-tech or 3-tech instead) and are responsible for the B and C gaps. The job takes bigger, heavier players who can handle plenty of double and triple teams without budging. The ideal nose tackle is close to 350 lbs (although most weigh quite a bit less -- the college ranks don’t produce many true 3-4 NTs), while the defensive ends (some teams prefer to call them defensive tackles instead of ends) weigh somewhere around 300 lbs.

3-4 defensive ends are much easier to find than their 4-3 counterparts, and indeed any of the defensive tackles on Seattle’s roster (especially the 3-techs) would probably do reasonably well manning the position. Nose tackle is a more difficult position to fill, plus it’s notorious for being one of the most physically intense and demanding jobs in football. However, if the Seahawks were only planning on running it a few times a game, the extra strain would be minimal. In any event, there are two players on the roster who might work: Brandon Mebane, who’s done an outstanding job at nose guard the past few seasons, and Colin Cole, whom the Packers tried their best to re-sign so they could plug him in as a nose tackle in their new 3-4 scheme. Red Bryant is a third possibility at nose tackle, depending on how well he does as a 4-3 nose guard.

Being a 3-4 d-lineman is not glamorous. They don’t get to make many tackles, and sacks are even rarer; players like Cortez Kennedy, who managed plenty of sacks from the nose tackle position, don’t come around very often. On top of that, if something goes awry in the 3-4, most of the time it’s because one of the three d-linemen missed a gap or let one of the o-linemen get loose. Still, it’s their hard work and sacrifice in the trenches that makes the linebackers’ jobs possible.

Tomorrow in part four we’ll take a look at how linebackers are used in the 3-4, examine the strengths and weaknesses of the 3-4 scheme, and finish off with a look at how and why the 4-3 and 3-4 are able to coexist in the modern NFL.