As our well-educated GK Brizer has already pointed out, we're not going to see teams unveil their blitzing or stunt defenses too much in the preseason games. That is something you want to save for the regular season—and definitely keep off tape prior to the games that count.
What we do have is a great opportunity to review the basic mechanics of a blitz and a stunt—and the difference between them.
There's a classic blitz look from the Eagles of yore. You've got a linebacker and a safety coming in to pressure the QB as the other linebackers and DE's drop into limited coverage.
Typically teams use man-to-man coverage when they first blitz. Blitzing is generally an anti-pass tactic used to overpower the blockers and pressure the passer. Because there are already more passing zones to cover than there are defenders to cover them, repeated blitzing usually forces the defensive team out of man coverage.
Sometimes we fall into old habits and use the terms "blitz" and "stunt" interchangably. This is not wholly accurate. "Blitzes" are defensive tactics that involve the defensive backfield (linebackers and defensive backs) charging through a hole. It can and should be used both to disrupt the pass protection and interfere with run blocking. Blitzing players must be carefully coached to break through the line under control and locate the football…and not get hung up on attacking the quarterback.
Stunting is a different technique. Stunts involve the linemen only. This illustration from Coack Derek Wade's playbook demonstrates a simple "cross" stunt involving the interior tackles. This is an advanced technique.
Occasionally you may hear terms like zone blitzes, "robbers," and cloud or sky coverages. These are pro-style tactics. Essentially, a zone blitz is an exchange of responsibilities between a linebacker and a defensive lineman. As the linebacker blitzes, the lineman drops back into the linebacker's vacated zone. Ideally the quarterback will recognize that the linebacker is blitzing and try to throw the ball into his area, where the lineman will be waiting.
Think of a robber as a zone blitz in reverse. The linebacker charges forward, and instead of a defensive lineman dropping into the vacated zone, a defensive back (usually the free safety) steps forward to cover the area. These techniques are effective largely because they change the basic zone landmarks, rather than because they confuse quarterbacks.
The last two terms, cloud and sky coverages, are designations for specific types of zone coverages. Most zone pass defenses are landmark-based. That is, the pass defenders drop to specific areas of the field. Because of this, once you know that a team is in zone, it is not too difficult to design your passing plays to hit the areas between the zones. Sky coverages bolster a specific area of field by rotating all the pass defenders towards that zone. (This can be useful against the run.) Cloud coverages confuse landmarks by dropping the linebackers deep and using the corners to cover the short zones.
One of the guys who's maybe best at coordinating all these defensive strategies in real time is Dick LeBeau, still going strong in his '70's as DC of the Pittsburgh Steelers.
He isn’t the father of the concept but can be credited with perfecting the scheme.
Today, we’ll travel back to 2012 Week Five—Steelers versus the Eagles— on a play where the zone blitz worked as well as LeBeau could have drawn up in his 40 years of coaching.
To start off, an aerial and end zone look at the Eagles’ formation. Empty set against the Steelers’ base defense with Brett Keisel (#99, DE) in a two point stance.
Off the snap, Keisel drops into coverage. McClendon and Hood slant one gap over to the closed side. That’s the key. That action causes center Dallas Reynolds and right guard Danny Watkins to slide with them. Woodley speed rushes to occupy the RT Herremans letting Timmons loop in between unblocked.
The last picture says it all. Six Eagles’ blockers working against three defenders. Take Herremans and Woodley away and it’s 5 vs. 2. Timmons comes in untouched. The ability to drop seven, rush four, and still have a player run in scot free? Music to any defensive coordinator’s ears…
Timmons misses Vick and Hood ultimately gets the sack but it was the zone-blitz pressure called by LeBeau that made the play happen.
As for the definition of the "Joker" defensive strategy?
In the Eagles defense, it's a player who moves around the DL pre-snap and may line up as a DE, DT, or LB. It's usually played by a DE or LB. And as the Great Sage-Lion JB99 has taught us over the years, it's not a true Joker unless the guy stands upright the whole pre-snap count. He cannot put his hand in the dirt at any point in the pre-snap count.
The Joker is usually a guy lined up at defensive end—he will stand up, and then will either rush the quarterback or drop back into coverage. I don't think that I would call a guy like Dallas' DeMarcus Ware (who stands up a lot on passing downs) a Joker, because as a 3-4 linebacker, his job description is pretty much just to blitz or play in a shallow zone or play in some light man coverage. The name comes because it's a position that people think you're messing with— and they're not supposed to know what you're going to do—basically you're "joking" with the opposing team and trying to confuse them, which would be by putting a man on the defensive line and dropping him back into coverage. Back in Andy Reid's and Jim Johnson's glory days, the Eagles used this often with Juqua Parker, Chris Gocong, and with Jevon Kearse, even occasionally with Trent Cole…
We'll see soon enough what Bill Davis and the Chippah have in store for us in the blitz and stunt departments…
And for sheer entertainment value, here is Eliot Shorr-Parks' latest guess at the Eagles' Final 53-man Roster as of August 20, 2013:
QB (3) : Vick, Foles, Barkley
RB (3): McCoy, Brown, Polk
WR (5): Jackson, Johnson, Avant, Cooper, Salas
TE (5): Celek, Ertz, Casey, Harbor, Carrier
OL (10): Kelce, Johnson, Mathis, Peters, Herremans, Barbre, Watkins, Reynolds, Kelly, Tennant
DL (6): Cox, Logan, Sopoaga, Thornton, Dixon, Curry
LB (8) : Ryans, Kendricks, Barwin, Cole, Graham, Matthews, McCoy, Knott
CB (6) : Fletcher, Williams, Boykin, Hughes, Poyer, Marsh
S (4) : Chung, Allen, Wolff, Anderson
Practice Squad: Momah, Shepard, Bamiro, Purcell, Tucker, Long, D. Dixon, Kruger, Square
Follow Eliot Shorr-Parks on Twitter at @EliotShorrParks