It seems that some around here, like some of the smarter sports writers in town, are clamoring for a change from a 4-3 to a 3-4 defense. I thought it would be worthwhile to take a look at the concepts behind the two schemes, the personnel requirements of each, and how the guys we have might (or might not) fit in.
But first off, let's be clear on what the 3-4 isn't: it's not a coverage scheme. It says almost nothing about what's happening in the defensive backfield. For those of you who lament the Vikings soft zones, rest assured that similar zones can be played behind the 3-4 too. We're only talking here about how you line up the front seven guys on defense, not about what's happening in coverage.
The rest after the jump.
First off, I'm no defensive genius. Heck, I'm not even a defensive reasonably-bright. Maybe I'm a defensive village idiot (is that an idiot talking about defense, an idiot who defends the village, or an idiot who lives in the village and is insecure?). Anyway fair warning, I tend to look at these things from a defensive lineman's perspective.
Let's start out with a general notion of what each option means when you're playing base defense (any manor of blitzes, stunts and coverages can be attached to either scheme):
First the obvious: ya got four down linemen and three linebackers. In general, all seven guys are responsible for one gap against the run. That means that the linemen are closer to being freed up to get after the passer because their primarily responsibility is only on one side of the offensive player lined up across from them. 4-3 is a defensive line oriented defense, and it's traditionally associated with teams that like to get after the passer. Like the Vikings (you may have heard of some old guys who used to like to eat purple people, or were purple and like to eat people of other colors, or whatever).
The obvious again: you swap one down lineman for an extra linebacker. Which really kind of sums it up. The point of the 3-4 is to substitute toward more athletic linebackers and diminish the role of the d-line. In the 3-4, generally the lineman are supposed to play two gaps. That means rather than pinning your ears back and going, you hold your ground, fight the man blocking you, and make a read as to where the play is going. This makes the lineman less dynamic, but that's okay, they are taking up blockers so that the linebackers behind them can run around and make plays.
The way I learned it, which might be wrong, is that the 3-4 is a newer scheme that was developed primarily as a way to more effectively stop the running game (I associate it with the old AFC). Linebackers are by definition harder for offensive linemen to block (because they aren't right across the line from them) and you use the three down linemen to get in their way.
For three of the linebackers, the personnel needs really aren't that different. You need three guys who can play the run and get back in coverage as necessary. The fourth backer tends to be primarily a pass rusher, who gets moved around the formation to bring pressure from where ever you want to aim it. The rush backer is similar to a 4-3 rush end, except, of course, that he often has to play standing up, and sometimes he will need to cover. Maybe that doesn't sound that different to some of you, but it sure does to me. Again, there's a lot more reading and a lot less letting it rip.
Things are different for the linemen too. Two of them are called ends, but they aren't really ends in the same sense as a 4-3 scheme, in that they aren't principally called upon to provide edge pressure. Again, they are generally playing two gaps and taking up blockers. Finally, the nose tackle position isn't that different from the 4-3 interior tackle, except that there is even more need to have him be a plugger who requires more than one blocker to move on run plays.
Ultimately, one big problem I see in switching to a 3-4 is I don't think we have the personnel. Let's take a look:
Nose: Remi Ayodele is the obvious choice, but he had trouble plugging this year in the 4-3. I don't think he's adequate. Assuming Guion or Evans are still around next year, they are possibilities, but neither really has the girth you're looking for. Both are more athletic guys who can provide a rush in addition to holding the middle. So, you know, they kind of tackles you want in the 4-3. I guess you could play Kevin Williams here, but again, that seems like a waste of his athleticism.
DE: Williams and Ballard would actually be pretty well suited to being 3-4 ends. The are good athletes for their size and could handle being bit further outside than they are in the current system. Brian Robison, Jared Allen and Everson Griffen, however, would be woefully wasted. They're pass rushers whose speed and athleticism would be underutilized as 3-4 ends.
Rush backer: The cup overfloweth, sort of. Allen, Robison and Griffen are all guys who could maybe play here. Each is a bit of a question mark in coverage, but let's assume one or more could figure it out. But the biggest problem I see is that there is only one spot in the 3-4 that makes sense for these three guys. That means two of them are on the bench most of the time. That is not good.
Other backers: So, you might say, well, how about using two of them as backers? Well, I don't know. I really don't like the thought of any of those three regularly trying to run with a TE or a guy out of the backfield in coverage. They are just too big, and I kind of doubt that any of them would enjoy that role.
I don't think we have the personnel for the switch right now. We'd need to trim at least one of our most talented defensive players, and we'd need to find a real run plugging nose.
But beyond that, I don't see the point. The Vikings have always played the 4-3, and always tried to have lineman who can rush. In a pass first league, why would we want to change away from that?
So, what do you think? And if you want to switch, what are you trying to achieve?