49ers playbook, Week 4: America Fire Zone blitz

This week’s installment of San Francisco 49ers playbook breaks down the America Fire Zone Blitz used in Week 4 against the Arizona Cardinals.


Today we are going to break down the America Fire Zone blitz the San Francisco 49ers employed in the first quarter against the Arizona Cardinals in Week 4.

First, it is important to understand what the fire-zone blitz is.

The fire-zone blitz involves a five-man pass rush with six defenders dropping into a zone coverage, usually a Cover 3. The purpose is to confuse the quarterback with who is going to pass rush:

The fire zone disguises pressure along the defensive front, and at the snap, the rush becomes three down linemen and two linebackers, or a linebacker and nickel/safety defender.

The fourth down lineman, usually and edge defender, will drop into an underneath zone on the opposite side of the blitz.

In Week 3 against the Los Angeles Rams above, the 49ers ran the basic fire zone. Pay attention to the defensive line and the edge defender that drops into an underneath zone.

Rushing five and playing a soft underneath proved risky here, as the Rams were able to get a 22-yard completion in the area vacated by the fire-zone blitz.

To negate that quick throw against five-man pressure, against the Arizona Cardinals in Week 4, another variant of the fire zone, known as the America Fire Zone, was employed early in the first quarter.

In this version, the defense rushes six defenders to create a wall and collapse the pocket, where that edge defender then becomes the sixth pass-rusher:

To make matters worse for the offensive line, the 49ers plan on stunting with Arik Armstead and DeForest Buckner.

Pre snap, the Cardinals are in 11 personnel (one running back, one tight end, three wide receivers).

The 49ers pre-snap movement shows linebacker NaVorro Bowman peel left before the snap. Post snap, him and K’Waun Williams, playing the nickel defender, blitzes from his nickel position over Cardinals wide receiver Larry Fitzgerald in the slot.

Linebacker Ray-Ray Armstrong begins to jump the shallow crosser before sinking into his middle-hook zone, while safety Jimmie Ward comes up to fill the underneath-hook zone on his hash.

Both Armstead (No. 91) and Buckner (No. 99) begin their stunt, while defensive linemen Solomon Thomas (No. 94) and Earl Mitchell (No. 90) slant across the faces of their blockers to their respective gaps:

Cardinals quarterback Carson Palmer initially looks to throw the underneath the crosser, but Armstrong immediately takes that throw away.

At this same time, Bowman and Williams are coming around the edge on their blitz assignments:

As Fitzgerald releases from the slot, Ward meets him in his underneath-hook zone and begins to bracket him with Armstrong, who sinks into the middle hook.

The Cardinals pick up the blitz, and Palmer immediately recognized that both middle of the field reads were quickly taken away as pass options, so he opens to his left to throw the downfield fade route:

Wide receiver John Brown is being trailed by corner Rashard Robinson.

Robinson is playing a common trail technique that allows him to bracket a receiver with the safety, Jaquaski Tartt, coming over the top from his deep middle third assignment:

Tartt does not get in there time as Robinson breaks up the pass. The 49ers dodge a bullet as the pass is underthrown and easily defensed by Robinson.

Had it been in front of Brown, that’s likely six points, as Tartt did not get over in time to provide help.

Recognizing that there were no inside seam routes and that the under receivers were well bracketed, Tartt should played the sideline a lot sooner to the short side of the field than he did.

Fortunately the pass went down as an incompletion:

For more 49ers playbook resources, see here and here.