While most of the MSM is talking as if Denver's conversion to a 3-4 defense is a foregone conclusion, there are many knowledgeable writers, including our own HT, who have expressed the idea that the 3-4 may not be a done deal. A number of us have talked about a “Hybrid” defense. While I know that many readers probably have a good idea what a hybrid might entail, I'm sure there are others who may have questions about it. This is my best attempt to explain what what I think we might be seeing.
First thanks to styg50 for his help with the graphics.
Just to set the record straight, my background is on the offensive side of the ball. So I hope that HT and others will point out any oversights or misstatements I make so that we can all become better informed.
To begin our look at a hybrid it might be helpful to start by looking at a "standard" 4-3 defense. The figure below illustrates a typical 4-3 defense. This defense is called a 4-3 Over. In line terminology when the center is not covered the alignment is called even, odd if the center is covered. A quick note on symbology. I grew up with a slightly different symbology. My coaches thought Vince Lombardi was God. So Vince if used Vs to designate defensive line therefore the only correct way to draw Xs and Os was with Vs and Os. Otherwise I hope everything else is self-explanatory.
While this is the typical figure drawn to illustrate the 4-3, in fact the position and alignment of the players can vary considerably based on the defensive play calling. Since many teams favor running to the strong side of the formation, defenses will sometimes adjust by also shifting to the strong side as shown below. This alignment is known as a 4-3 Over. Notice that the Mike LB is partially shadowed by the RDT. This alignment makes it more difficult for the defense to get a clean block on the MLB, which can cause problems for some offenses.
While most teams tend to run to the strong side, a number of teams do not. When Shaun Alexander was in his prime the Seahawks actually preferred to run to their left behind Walter Jones and Steve Hutchinson (two All-Pro lineman will do that for you). Under Marty the Chargers used to run weak side quite a bit as well, as did the Broncos when Zimmerman was on the left. To counteract a tendency to run weak side some defense will "Under" shift the line to a 4-3 Under. Notice that, even though the Mike is bubbled over the guard (there's no blocker between him the the O-lineman) it's still difficult for the guard to drive out to block the MLB without exposing both the A and B gaps on the strong side.
Now imagine if we split the RDE (on the left side of the picture) a little farther out and set him back about half a step. Then we have a formation like that shown below:
If you look carefully you'll notice that this looks awfully similar to a 3-4 defense. It's also very similar to the defense the Cardinals used in the playoffs. Actually, if you watched the Ravens, this is basically the defense they use when Terrel Suggs is healthy. How is this different than a 3-4? the real difference is in the player I've labeled "P." In a 3-4 this would be the ROLB; in a 4-3 Under the RDE. In the Hybrid defense this player is a, wait for it, "hybrid," a combination DE/LB. In the Cardinals system this position is called the Predator. That sounds like a much better football term than LB/E so I've labeled the position with a P.
How it Plays Out
Look at how this formation plays out. On a run to the left, the guard can't get out and block the MLB without exposing the A and B gaps. The SLB, SS, or CB can force on any run to the outside, depending on the formation, and there's always the threat of the Pred running the play down from behind. On a run up the middle, the RG still has a poor choice on blocking, the LT has a bad angle on the WLB and there's still the risk of the Pred undercutting the play form the outside. Finally, on a run to the weak side the tackle can't get out to block the Pred or WLB without exposing the edge to the LDT. Even with help from a FB there's no one to cut off the MLB.
How it Fits the Broncos
One of the problems with the 3-4 is that it just doesn't fit the Broncos current roster. Not only are there no obvious immediate solutions at NT, but a number of current contributors don't fit well with a 3-4. Not so with the Hybrid. At Pred, both Doom and Moss can contribute, Doom as a pass rusher, Moss for his ability to play in space. Thomas is a perfect fit at RDT and Woodyard/Winborn become a formidable tandem at WLB. Larsen may be good rotating with DJ at Mike and Boss fits at Sam. Or, if Boss's injuries are too big a concern DJ can move back to Sam. LDT is a bit of a problem since we'd really like someone who demands double-teaming in order to keep the RG off the MLB. But it's proabably easier to fill that role than to find a true NT. Powell may be able to play, D-Rob may return to form, or we may have to grab someone off FA. At RDE Ekuban provides a good pass rush and Peterson, Clemons, or even Crowder may be able to fill in on running plays.
So will this modified 4-3 Under become the Broncos base defensive formation? I think the answer is sometimes. Most teams are only in their base formations maybe 40% of the plays anyway. In the Super Bowl I think I counted that the Steelers were in their base 3-4 less than 25% of the plays. Against some team, in some situations, I expect the Broncos to play something lie what I've described. At other times, say against team that want to run it up the gut, or go with two or three TEs, the Broncos may go back to a 4-3 Even, going so far as to remove the Pred, move Thomas out to a 5-technique and putting Peterson or Clemons in a 2-technique. One advantage of having lots of indistinct players is that you have lots of options and you don't lose much by substituting one player for another.
to give you an idea of the flexibility of a hybrid defense consider the following scenario. Second down and intermediate. Based on down and distance you expect the offense to pass but you don't want to bring in your nickel and expose yourself to a run.
Your P takes a hard edge rush. The RDT fakes an outside rush, then drops into coverage. Will delays then blitzes into the hole vacated by the LG following the RDT. Mike cheats up to the line and fakes a blitz before dropping into coverage while the LDT takes a hard charge into the A-gap. Sam fakes an edge rush and drops into the flat while the LDE also takes a hard edge rush. The SS checks the TE and seeing him stay into block, blitzes into the B-gap. The RG has a dilema: help the C or block the SS. Ultimately it doesn't matter because Will has come through unblocked since the FB went out to help on the Pred who had come free on the edge.