Inside the Playbook | Part Three: Inside Zone, Split Flow


Over the next few months, we are going to spotlight offensive c,oordinator Brian Daboll’s offense. Daboll entered the NFL in 2000 with the New England Patriots, and over the course of the next 16 seasons, he held several positions, including Defensive Assistant, Wide Receivers Coach, Tight Ends Coach, Quarterbacks Coach, and Offensive Coordinator. When the opportunity arose to jump to the college ranks at Alabama, Daboll seized it. As the offensive coordinator and QB coach at Alabama, he got to learn from one of the best organizational managers, but he also got a chance to work with college talent and to incorporate some college concepts into his playbook. This could be extremely useful because more and more of those concepts are seeping into NFL playbooks. The move worked, and it landed him an offensive coordinator gig with the Bills. This series is meant to give you an idea of what is available and taught in Daboll’s offense; it doesn’t necessarily reflect the extent to which he will use these concepts, though. I will be periodically using cut-ups from Charlie Weis’s playbook to give you an idea of the terminology and basics of the concepts.

Part One: Play structure and terminology

Part Two: Outside zone, Pin and Pull

Base Offense: Run Game

In every playbook, there is a core set of plays and concepts that a team hangs its hat on. Base offensive concepts are typically run on 1st and 2nd down, or even on critical down-and-distances. For Brian Daboll, another base concept is inside zone. Unlike outside zone, where the offense wants to stretch you horizontally, inside zone is more of a power, downhill running concept. The offensive line wants to create vertical displacement, re-establish the line of scrimmage and run the ball down your throat. According to SportsInfo Solutions, in 2017, the Crimson Tide ran 122 inside zone runs, for 589 yards and 12 touchdowns.

Inside zone via the Alabama 2015 playbook

There are many schools of thought on how to teach zone blocking to the offensive linemen. Some coaches use a numbering system to identify who the linemen will block. In this system, the center identifies a ‘Mike’, and that player is assigned a number (0) and typically blocked by the center. That won’t always be the middle linebacker; it technically will be the first inside linebacker to the play side. Why are they identifying a Mike? Because zone runs always work to the Mike linebacker. After the Mike is identified and labeled, then each defender receives a number based on that call. So on the play below, the play side guard blocks the first defender 1, play side tackle 2, and the play side tight end 3. The backside guard will block the -1, backside tackle -2 and the backside tight end -3.

Some coaches teach linemen the concept of covered or uncovered. The parameters do vary, but for simplicity’s sake, we’ll say that covered is if the lineman has a 1st level defender over him or anywhere up to his PLAY SIDE teammate. On the snap, the offensive linemen step in the same direction, in the direction of the play call. Linemen who are covered, end up blocking the man over them. On the play below, you will see the left tackle, left guard, right guard and tight end block the defenders over them.

The right tackle is uncovered, so he is responsible for his play side gap, which is the B-gap. He is tasked with climbing to the second level to pick up the linebacker. Due to the alignment of the nose tackle and action by the defender post-snap, the center and guard must execute a combination block to the Mike linebacker (0). The key is not only to secure the block of the nose tackle, but also to try to get any sort of movement possible before picking up any second level defender. On the snap, the center quickly wrong steps to hold up the defensive tackle and to give his teammate enough time to overtake the block, then he picks up the Mike linebacker who is attempting a run-through.

The running back out of the shotgun is aiming for the play side foot of the center. He is taught to read the 1st down lineman outside the A-gap. The read and decision need to be quick so that the back can get downhill. He does on this play, and the bend gets him into the end zone.

Securing the first level defender is the main coaching point, and that is why this concept is seen as more powerful than outside zone runs. Later in the game, Alabama runs inside zone weak again, and the linemen do a tremendous job of securing the down linemen by executing two combination blocks before they pick up the linebackers.


Split Flow

Split flow zone or ‘divide zone’ is the same blocking scheme, but now the offense uses a fullback or tight end to confuse the defense. Often times, linebackers are taught to read the near lineman to the fullback, so offenses will use split flow to create false reads. Split flow is created with the direction of the play to the defense’s right and the tight end going against the flow to the left to kick out the end man on the line of scrimmage. The ball is going one direction, and the blocking is going in the other.

This action essentially splits the defense in half, often causing defenders to hesitate in an attempt to read the actual flow of the play. The blocking up front and aiming point for the running back are all the same. The back is reading the first defender outside the A-gap.

The defensive end #99 is caught in a bind. The right tackle looks like he is executing a down block, and the tight end is coming in his direction, so he doesn’t squeeze the run. This leaves a huge lane in the C-gap, and the RB’s reads help him find the crease.

In the red zone, that split second hesitation by defenders can make all of the difference. Alabama runs split flow zone, and the false read causes the second level defenders to pause. Running back Bo Scarbrough is able to walk into the end zone.

Finally, Daboll shows off the versatility of his offense on this play versus Colorado State. On prior plays you had the line blocking inside zone, then I showed you split flow; well, here is a split flow zone run with a backside TUG call, paired with a run-pass option (RPO)! Let’s break it down:

First, Daboll has a bubble screen/hitch route combination called on the RPO. The run-pass option appears to be predetermined before the snap, so he is likely counting the defenders in the box. With six defenders in the box and six blockers, the offense has a hat on a hat, therefore they don’t execute the pass.

Now to the run portion of this play; it’s typical zone blocking scheme on the front side of the play. The center and right guard are going to combo block, secure that down defender, then climb to the second level. The right tackle is going to kick out the end. The backside blockers, the left guard and left tackle, execute a TUG fold block, which stands for Tackle Under Guard. On the snap, the guard will pin the defensive tackle and the tackle will pull and block the inside linebacker. But it doesn’t end there; the tight end is executing the kick out block across the formation. So the defenders have two false reads: the fold block and the tight end’s split flow.

That completely crosses up the defense; it pulls the linebacker and secondary run support player, the safety, out of position, and RB Bo Scarbrough scores. This kind of play should excite Bills fans.

After sitting through an entire season of run game struggles under Rick Dennison and his wide zone scheme, it will be refreshing to see the offense get back to a downhill running game. By incorporating some of these inside zone runs and tags, the Bills should be able to get LeSean McCoy back on track.