Anyone who's ever played a game of Madden NFL knows that there are all sorts of defenses that football teams run these days. It's slightly different and a bit more complicated than the days of backyard football when the only defensive rule was having to count to five mississippi before you could rush the quarterback. While I am by no means an expert in NFL defenses knowing the difference between the 4-3 defense and the 3-4 defense (which the Patriots run) can prove to be helpful around draft time as many of the players are better fits for one system or the other.
This article from Pro Football Weekly breaks down the all-time greats of the 3-4 defense. It's interesting that Ron Borges wrote the article, he used to work for the Boston Globe where he blasted Bill Belichick for what he thought was wasting a pick on Richard Seymour. In the article linked above Seymour received votes for being the best ever Defensive End in the 3-4. Here's what Borges had to say about him way back when:
On a day when they could have had impact players David Terrell or Koren Robinson or the second-best tackle in the draft in Kenyatta Walker, they took Georgia defensive tackle Richard Seymour, who had 1 sacks last season in the pass-happy SEC and is too tall to play tackle at 6-6 and too slow to play defensive end. This genius move was followed by trading out of a spot where they could have gotten the last decent receiver in Robert Ferguson and settled for tackle Matt Light, who will not help any time soon. - Ron Borges, MSNBC after 2001 Draft.
As a responsible blogger I wish there was a link to it but luckily the stupidity of the statement has allowed it to live on in infamy on the internet. Anyway, this isn't a blog about Ron Borges' incompetence, Cold Hard Football Facts already did that, it's about the 3-4 defense and how it works.
Let us begin with the three defensive linemen, for the Pats that means Richard Seymour, Ty Warren and Vince Wilfork. Bill Belichick used first round draft picks on all three of these guys and that demonstrates how important they are to the defense. While the goal of defensive linemen in the 4-3 scheme is to get to the quarterback, their goal in the 3-4 is to take on opposing blockers and hold their ground. This is why someone like Wilfork is so good as a nose tackle. At 6' 2" and 325 pounds he has the size and can gain the leverage necessary to take on two blockers at a time without losing ground. The same with Seymour and Warren on the ends, they are stout and require at least two blockers to move them anywhere. USC's Sedrick Ellis and LSU's Glenn Dorsey are both players in this years draft who could fit into this role for the Pats.
While the defensive line is holding up the blockers it's the job of the linebackers in the 3-4 to make the plays. The 3-4 allows the defense to blitz from numerous different attack points. This can confuse offenses, especially when the opposing quarterback is unsure if someone like Adalius Thomas is playing Inside Linebacker or Outside Linebacker on any given play. This is why Belichick values versatility in his linebackers - it allows him to disguise what his defense is doing.
Outside Linebackers in the 3-4, players like Rosevelt Colvin, Lawrence Taylor and Shaun Meriman are pass rushing terrors who can also drop into pass coverage. They need to be able to run and cover Tight Ends but they also get all the glory with the majority of the sacks. With Colvin no longer in the fold it looks as though Mike Vrabel and Adalius Thomas will be the starting OLB in 2008 but there are some solid players in this years draft crop that would be welcome additions and add an element of speed.
Inside Linebackers in the 3-4 like Tedy Bruschi, Patrick Willis and Harry Carson have to be tough mofos. They have to be able to take on Guards, defeat them and get to the ball carrier. They don't have to be the fastest or most athletic guys on the field, most often they can get by with superior intelligence - reading the play and reacting before the big uglies from the offensive line can get their paws on them. This is why Belichick prefers vets like Victor Hobson and Junior Seau at ILB - they might not have the young legs anymore but they will rarely be out of position and know what the offense is trying to do within moments of the ball being snapped.
The Patriots are well known for never having taken a linebacker in the first round since Bill Belichick's regime took over but this could be the year that changes given the abundance of talented Defensive Ends and Linebackers in this years draft class. What makes it most difficult to draft linebackers for the 3-4 is that not many college teams run the scheme as a defense. Thus players like Ohio State's Vernon Gholston, Florida's Derrick Harvey and Auburn's Quentin Groves played their college careers as 4-3 defensive ends. Projecting how they will do when being asked to stand up and cover tight ends in the passing game is hard to do. But ultimately there are a few like Shaun Meriman who are able to not only make the transition but dominate.
There are only a handful of teams running the 3-4 these days in the NFL. The Steelers, 49ers, Browns and Jets are just a few of them with the Miami Dolphins rumored to be making the transition as well. It's a versatile defense with specific needs at the defensive line and linebacker positions. With each team that switches to it the less players become available who fit a 3-4 teams needs. So it doesn't help having both Miami and the Jets selecting before the Pats.