In order to succeed in the National Football League, teams simply need to understand when its time to transition from the past to an ever-changing landscape of the future.
Offenses have done this to an extent throughout the history of the league, but defenses seem to be slower in the adaptation process. Some of this has to do with weaknesses as they relate to archaic schemes and strengths as they relate to offenses that are revolutionizing the league.
The increased usage of 3-4 defensive scheme is a prime example of teams finally finding out how to go up against new offenses in the passing era.
While the 4-3 and 3-4 remain the two main schemes in the NFL today, there are other defenses that are making their way around the league, mostly as variations of those two schemes.
Let's take a look at some of the strengths and weaknesses of the top defensive schemes in the NFL today.
Note: Though teams run base 3-4 and 4-3 "schemes," there are variations that each defense employs. Three of the "schemes" explained in this article will be variations that run off the 4-3 or 3-4 concept.
The 3-4 relies on stronger/bigger defensive linemen.
The 3-4 defense requires much different personnel than the base defenses that we have seen in the NFL in the past.
The first point of emphasis is acquiring larger defensive ends, who can open up pass-rushing lanes for outside linebackers. Without this, a defense may struggle getting to the quarterback on a consistent basis.
The second point of emphasis, and this is a biggie, is finding speedy edge rushers. These outside linebackers must be able to get to the outside and push past stronger offensive linemen.
Defenses who employ the 3-4 usually tend to focus primarily on building a strong front seven, while making the secondary stronger due to the specific scheme. This means that front offices of teams who employ this scheme tend to focus less on upgrading the secondary.
All of these things must occur if a team is going to have success utilizing this defense. If not, struggles will ensue.
Versatility and complex alignments are two big benefits for a 3-4 defense. It can cause mass confusion for offenses, which will lead to broken blocking assignments and more sacks. Couple this with the reliance on stunts and what I call "blind blitzes" and you have the perfect storm for success against more athletic offenses.
As we saw with Aldon Smith in San Francisco last season, you will see outside linebackers lined up as defensive ends. This causes issues for less athletic offensive tackles in pass protection and will enable the defense to put consistent pressure on the quarterback.
This type of defense can also mask issues in the secondary. Teams don't necessarily have to possess shutdown cornerbacks and can focus on stacking up on talent in the front seven.
Due to the fact that the NFL has fully entered the passing era, this defense has become more prominent than in the past. A lot of that has to do with being able to control passing offenses from the front seven, which can throw off the timing of the quarterbacks and receivers.
In order to be successful running this defense, teams need to have the right personnel all over the field. They need a run-stuffing nose tackle, which is a rarity in the NFL. In addition, they need to find pass-rushing outside linebackers. That can be troublesome, as most front offices attempt to move college prospects from a hands down defense end position to a hands-up outside linebacker position.
They also need beefier defensive ends to create pass-rushing lanes for linebackers.
Again, let's look at Aldon Smith in San Francisco. Once Justin Smith went down to injury, the young linebacker struggled a great deal getting to the quarterback.
It's fine and dandy to have athletic outside linebackers, but defenses that employ this scheme must be able to find defensive linemen who can fill gaps.
As we have seen in recent history, prospects attempting to make the transition from defense end to linebacker don't pan out a majority of the time.
If any of these positions are lacking, a defense will struggle a lot. This is only magnified if said defense doesn't have above-average personnel in the secondary, which would have normally been masked by a strong front seven.
As with Michael Johnson and the Bengals, the 4-3 relies on more athletic defensive ends.
Unlike the 3-4, this base set seems to be more widespread to the point that a defense can utilize a wide array of personnel in implementation of it.
We see teams today bring forth many different sets from a 4-3 scheme. The Seattle Seahawks run a hybrid scheme, that seems to take a lot of fine points from the 3-4 defense.
An example sits with Seattle's defensive end Red Bryant. He is of the run-stuffing variety and helps open up lanes for outside linebackers, who tend to rush more than in the traditional 4-3.
Other teams who tend to run the more traditional set must find a happy medium between staying true to the history of the scheme and adapting to the changing landscape of the NFL.
This scheme tends to be better against the run. It enables linebackers to roam free past the line of scrimmage and go sideline-to-sideline more often. That forces offenses to find a way to get the ball carrier outside against a more stout linebacker unit.
Where the 3-4 might focus on pushing the line against the pass and pressuring the quarterback from the middle three, the 4-3 will rely more on acquiring pressure from the front four. Again, this helps draw rushing attempts to the outside.
As we saw with Luke Kuechly and Bobby Wagner as rookies last season, youngsters playing middle linebacker can make a more immediate impact. Their roles are more defined early on, which makes for a decreased learning curve.
This scheme also enables cornerbacks to cover a spot on the outside with cover safeties attempting to roam free over the top. Outside linebackers may be tasked with maintaining the gap at the line with inside linebackers dropping back between the hashes less often.
The 4-3 might be stronger against the run, but will struggle more than other formations against the pass.
As with most defensive schemes, if you don't have the personnel; there will be struggles. If a defense doesn't have more athletic defensive ends or cover inside linebackers, it will be exposed. In addition, elite quarterbacks will be able to spot deficiencies in this type of scheme much easier than they can in the 3-4.
As I mentioned before, roles are more defined. This doesn't even take into account that defenses are limited in terms of what types of alignments they can run prior to the snap.
A good offensive game plan can recognize these issues and take full advantage, which has increasingly become an issue in the new NFL.
That's a primary reason for the recent trend towards the aforementioned 3-4.
Could Quinton Coples be used in a hybrid role?
The 46 defense is a hybrid of the 4-3. It focuses more on developing a point of attack in the box, usually with eight men, and drawing the offense into having to force the ball over the top. Teams used to utilize this defense all the time, but it has become a bit of a rarity in the NFL today.
Defenses do use this against offenses that aren't able to show a consistent passing game. An example would be teams that went up against Christian Ponder and the Minnesota Vikings last season. Ponder struggled getting the ball over the top and Minnesota had one of the best running backs in the game in the form of Adrian Peterson on the ground.
You will continue to see this hybrid scheme utilized when defenses go up against relatively weak pass offenses.
The issue here, however, is that it leaves the defense vulnerable to shots down the field. Once a passing attack is successful going up against this scheme, it tends to struggle making in-game adjustments. Despite running a base 3-4, the Houston Texans utilized this philosophy against Jacksonville last season.
The result wasn't too great for Houston.
Jaguars quarterback Chad Henne threw for 354 yards and four touchdowns. Houston did end up winning the game in overtime, but its defense wasn't a primary reason for that.
The idea here is to send more pass rushers than the offense can handle. Footballguys.com explained exactly what this type of scheme is meant to do.
Most descriptions of the 46 defense talk about pressure. For Ryan, it was more than that. He was sending six defenders on almost every play, except when he was sending seven or eight. The persona of the scheme and its parts was meant to be relentless, intimidating and destructive.
His defense set scoring and yardage records. In one season in Houston, Ryan's Oiler defense knocked nine starting quarterbacks out of games either with injury or because of poor play.
Pressure, pressure and more pressure. That's the idea. If utilized correctly, this will cause confusion on offense and a lack of timing in the passing game. It also enables a defense to run less-than-stellar defensive backs on the field.
One of the primary reasons that this defense has become somewhat obsolete in the NFL is that offenses have been able to adjust to mass pressure. They can keep more blockers in, which enables the quarterback more time to pass the ball.
When given time to pass, the quarterback will see single coverage on the outside. The San Francisco 49ers of the 1980s really did a great job exploiting this scheme.
While teams may utilize the 46 as a subpackage of sorts in the NFL today, it isn't used as a primary scheme.
For good reason.
Can you imagine a team utilizing this type of scheme against the Aaron Rodgers of the world? It would literally get picked apart in every conceivable way.
Detroit started using the Wide-9 defense to feature its solid defensive line.
The wide-nine asks defensive ends to pin their ears back and go after the quarterback, while linebackers fills the gaps against the run.
It is an interesting monster simply because defensive ends in this scheme aren't asked to focus on the run or utilize stunts at the point of contact. Instead, it's all about going up field on nearly every single play.
In essence, the wide nine might be more of a technique than a defense, but some teams utilize the formation as its base defense.
The Detroit Lions come to mind first.
Cliff Avril was poor against the run during his stint with the Lions, but he was extremely important to the defense because he wasn't tasked with stopping the run a great deal of the time. If utilized correctly, a defense can mask these issues against the ground game.
Consistent pressure from outside the tackle. You will see defenses force max protection at the line, which could throw off what an offense is trying to do during a game.
By virtue of selecting Ziggy Ansah in the first round of April's draft, Detroit answered criticism of it utilizing this scheme by acquiring a youngster that seems to fit it to a T.
Ansah will be lined up wide, far off the tackle, and be asked to get to the quarterback on a consistent basis. This will be his only task as a rookie.
If successful, Detroit will be able to force more turnovers by putting a ton of pressure on the quarterback. It will also enable the Lions to mask perceived weaknesses in the secondary.
There is a reason why defenses don't utilize this scheme a majority of the time. It puts an emphasis on pressuring the quarterback, but tends to ignore the run game. In short, offenses can exploit this scheme by committing to the ground game.
Smart Football had an interesting take on exactly how offenses can exploit the wide nine:
...This technique...obviously opens up all kinds of issues in the run game: the defensive end aligns so wide the interior offensive linemen can quickly get up to the second level defenders like the linebackers, and the defensive ends are easy marks for traps, draws and counter plays as they sprint upfield.
Here is a prime example of giving a running back too much green field, which happens all too often in this scheme. Adrian Peterson might look like he is flying through the hole, but in all honesty you could drive a bus through that lane.
It remains to be seen just how much teams, including the Detroit Lions, will continue using this scheme with the advent of the pistol offense at this level.
Just on the surface, defensive ends who get up the field would leave a ton of open areas for either the quarterback or the running back to go through on the ground. In addition, asking a linebacker to cover this new formation might be an unenviable task for said linebacker.
Just ask Erik Walden (via Niners Nation).
DeMarcus Ware and the Cowboys will start using the Tampa 2 under Monte Kiffin in 2013.
The Dallas Cowboys plan to use a variation of the Tampa-2 defense this upcoming season under new coordinator Monte Kiffin, who popularized it in Tampa Bay.
One of the main ideas of this defense is to run through the middle linebacker, who reads what type of play the offense is running. He will drop back into coverage on pass plays or attack the ball carrier in run support.
This set is normally employed as a 4-3 hybrid and was originally created to go up against West Coast offenses.
In reality, it is meant to help the back end of the defense by creating what can be called a "three-safety set" with the middle linebacker dropping further back than in the traditional Cover 2.
A defense that possesses ultra-athletic players will normally be successful running this scheme. In addition, if the players know their responsibilities, it will be difficult for offenses to run or pass up the middle.
It works extremely well against offenses who rely a great deal on the draw or go to their tight end on a consistent basis.
The Tampa-2 also enables defenses to cover over the top and stop the deep pass. We saw this a great deal with the Buccaneers back in the late 1990s and early 2000s.
Considering that the middle linebacker is asked to drop back into coverage and guess what type of play the offense is running, teams have success running to the outside against the Tampa 2. They can spread the field to the outside and play more of a horizontal game.
Offenses tend to be able to move the ball down the field in a timely manner against the Tampa-2 if the defense doesn't have the necessary personnel.
In addition, teams that utilize the Tampa-2 will have a hard time going up against more athletic backfields. By this I mean, both quarterbacks and running backs. They are also vulnerable against the pistol, wildcat and read-option formations.
Few NFL teams have had success running this scheme.
Vincent Frank is an NFL featured columnist at Bleacher Report.