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Defensive scheming

Posted by Chase Stuart on November 9, 2009

I've got a theory that there aren't necessarily teams that can only play the run well or can only defend the pass; rather there are just good defenses and bad defenses (and everything in between). Certainly there are teams that have played well against just the run and not the pass, and vice versa; there's no denying that looking backwards, certain teams in certain years were great in one area of defense and terrible in the other. But looking backwards, there are teams that recover lots of fumbles and teams that faced opposing kickers who missed a high number of field goal attempts, but that doesn't mean that those things will happen again in the future.

My claim is that theoretically -- i.e., if we played 1,000,000 games so that randomness would be eliminated -- defenses should just be defenses. No good run-D, bad pass-D teams; no average run-D, excellent pass-D teams; just defenses. That (I think) is a bold claim, so I better have some good reasons behind it. What are they?

1) Defenses are like chains: they're only as strong as their weakest links (for the flip side to this argument, see Brian Burke's article that offenses are like chains). Picture an unbelievable run-D teamed with an awful pass defense. That defense isn't going to be very good, as almost every team in the league could pass on them all day long. Flip the script, and nearly every team could control the game with power football against a defense that can't stop the run. On defense, if you have a weakness, almost every opponent can exploit it.

2) What's that mean? Defensive coordinators should tailor their defensive strategies to cover their weaknesses. When we think of a strong run defense, we think of a beefy defensive line and some hard hitting, agile linebackers. Pretend you're a defensive coordinator with what appears to be the elements of a team with a great run defense and a terrible pass defense. You've got two big defensive tackles, two run stopping DEs, a run-stopping set of linebackers, a hard hitting strong safety that's a liability in coverage, and some weak cover corners. What do you do?

Here's what I would do. I'd say my guys can stop anyone in the running game and we'd still allow 42 points because our pass defense is so bad. So I'll tell my OLBs to either blitz or drop into coverage on most plays; I'll play a nickel defense pretty frequently, since I still should be able to stop the run with that package. I'll never put a safety in the box; if I want to have my SS stop the run, since that's what he's good at, I'll be sure to put him close to the line of scrimmage but I'll also take out a linebacker for another corner. I'll blitz the passer frequently to protect my weak corners, but I'll counter that by occasionally dropping my DEs into coverage since they're not going to get to the QB, anyway. I will do as much as I can to cover for my bad pass defense. On some plays I'll have just a two-man rush and have nine guys playing the pass. Most likely, I'll field six defensive backs on more plays than any team in the league, especially since my SS is mostly just another linebacker, anyway.

Do you think I've gone too far? Let's say that even though based on talent and ability I have the #1 run-D and the #32 pass-D in the league, my defense's statistics (measured in terms of effectiveness, not gross yards) say we have the #10 pass D and the #20 run D? If that ends up happening, I'll just creep back a bit. I'll stop dropping my DEs into coverage. I'll make sure I don't take out my slow but powerful MLB too often. I'll play more nickel and less dime. In other words, I'll keep tweaking my defensive lineup and scheme until I achieve balance.

The same is true if you have -- based on talent -- the best pass D and the worst run D. Let's say that you've got great cover corners, two terrific edge rushers, former college safeties at linebacker, a converted free safety at strong safety, and two agile interior linemen. You're worried, though, that your run D is going to get murdered and you're going to lose every game. So what do you do? You play 8 -- or maybe 9 -- in the box. You tell your edge rushers to hesitate for a second before selling out on the pass. You tell your corners to keep an eye on the running game. You don't go to the nickel even if your opponent brings a third receiver onto the field. And so on.

Just like with the stud run-D roster, with a stud pass-D lineup, you can keep tweaking your makeup until you achieve perfect balance.

This theory isn't perfect -- there are some minimum thresholds of ability a player must have. Dwight Freeney's never going to be able to play the run as well as other ends. A 35-year old John Lynch could only do so much in the passing game. Against the Browns, you really don't need to worry about the pass beating you. But generally, or as long as you and your opponent are not too elite/poor I think, teams can -- and will -- do whatever they can on defense to ensure perfect balance.

There are definitely exceptions. The Colts are the best example, as they've been specifically created to stop the pass. The Colts have limited resources to spend on defense, and with their great offense, are banking on needing to play good pass defense more often than good pass defense. Because of that, they've got speedy edge rushers in Freeney and Mathis, and historically, had light but fast players in the interior of the defense. They're not even trying to be good against the run.

Outside of Indy, if you've got slow cover corners, there's not much you can do. If your team is full of bad tackles, no amount of positioning or scheming will ensure success against the run. You may throw extra cornerbacks on the field to sell out against the pass, but if your GM left you shallow at cornerback, there's not much you can do during the season (in the off-season, you can request new corners). If you're hit by injuries and lose your top three defensive tackles, you're going to struggle against the run.

Are there so many exceptions that they swallow the rule? I don't think so. This is all just theory, though. What do the numbers say? Check back tomorrow.