Zone blocking is one of the most discussed - yet least understood - strategies in football today.  There are nearly as many different opinions on zone blocking as there are people who have heard of zone blocking, and most of the debate comes from people who couldn't tell you the first thing about how a zone block differs from a man block.  So with Tennessee adopting a "100% Zone" blocking scheme, I felt it was a good time to go through some of the basic concepts of zone blocking so that we can have a more intelligent conversation on it.  Here, I'll use a standard play - the stretch sweep with inside zone blocking - to illustrate how zone blocking works.  It's one of the simplest situations to illustrate as well as one of the most devastatingly effective runs available to a team willing to commit to it.

Overview

If anybody ever asks you what zone blocking is, the shortest possible answer you can give is that the linemen block zones rather than block defenders.  (If the asker is particularly annoying, you can always say that in a matter-of-fact, how-could-you-not-already-know-that tone.  Very effective.)  Digging a little deeper, what this really means is that the linemen are looking for specific areas of the field to block; if a defender happens to be there, they block the defender in such a way as to control the spot.  If a defender isn't there, they continue toward that spot, offering double-team assistance only if it's convenient.  Once they control a zone, if they're not fully engaged, the linemen can then look to the "second level" for somebody in the defensive backfield to block (on run plays).

The reason teams came up with zone blocking is rather simple: big, hulking offensive linemen who are agile enough to keep up with defensive shifts are hard to come by.  In the NFL, the problem is quite simply that there are not enough quality big linemen for every team to assemble a dominant offensive line.  Instead of competing against 31 other teams for a scarce resource, some teams sought to find ways to use smaller, quicker linemen effectively.  Because of the acknowledged weight disadvantage these linemen would face, the goal was to scheme away from the straight-up shoving contests and find ways to maximize leverage on the opponent.

As we step through the following diagrams, keep these principles in mind.

The ideal linemen for zone blocking are:

• Quick, even at the cost of size.
• Disciplined, even if the assignment seems pointless.
• Consistent, not giving visual cues to the defender as to their initial intention.
• Smart, able to keep up with defensive shifts before the snap.

The ideal running backs for zone blocking rushes are:

• Disciplined, willing to do their job and not improvise.
• Decisive.
• Crisp runners - not necessarily fast, but they must have sharp cuts.
• Committed, willing to blast toward a gap that doesn't exist - yet.
• Decisive.  No, really.  A backfield dancer is absolutely doomed.

Those characteristics in runners and linemen are relatively cheap to come by in the NFL draft.  For years, Denver was the only team that was fully committed to a zone blocking scheme; during those years, their best linemen and runners were routinely found on the second day of the draft.  Just as routinely, Denver was cranking out a different 1,000-yard rusher every year, subsequently selling them off to other teams for capital to be spent later.  Meanwhile, the rest of the NFL was tripping over themselves to get the top-rated players at these positions.  (Recently, the significant increase in the number of zone blocking teams has changed the market, and Denver spent a #12 pick on an offensive lineman last year.)

The point is that you don't have to have the superstars to run an effective system.  While that always helps, zone blocking was an advent created to atone for talent shortfalls.  So let's see the zone blocking principles.

ZONE BLOCKING AGAINST A 3-4:

I will start against a 3-4 because the principles are easier to diagram.  Before running a play, I will first highlight the primary reads that the lineman must make before the snap.  Then, I will show the first two steps taken by each lineman and how those steps are geared toward zones rather than defenders.  (This is, after all, the core principle in a zone blocking scheme.)

In the first diagram, you see the front seven of a 3-4 defense and the line, quarterback, and halfback the offense.  (The defensive ends are split a little wider than usual for a 3-4 for the sake of illustrations to come later; the principles will be unchanged.)  Now, let's take a look at the most basic presnap reads that the offensive linemen must make.

In this zone blocking scheme, there are only two different reads the linemen must make.  If they are "covered" like the tackles and center in the diagram, they think "stretch and block".  If they are "uncovered" like the guards, they think "stretch and assist".  They will be seeking a position in which they have a leverage advantage over the defenders.  They are not looking to overpower the defenders.

Looking first at a covered defender:

The first step is shown here by the tackle's change in position.  It's a lateral move for position, not a forward move for blocking contact.  (We're neglecting a huge discussion on footwork here, which is absolutely key to the system.  Assume that the lineman has the right footwork to take this lateral step without giving up his ability to keep his balance if shoved.)

The sideways motion accomplishes two things.  First, it places the lineman in a position to block the defender at an angle rather than straight-on.  Second, it offers the defender a place to run where the lineman might be able to block him out of the play.  (As you'll see later on, this is a lose-lose proposition for the defender:  if he steps into the gap, he loses the ability to pursue the play to the outside; if he slides outside with the tackle, he will leave a hole for a cutback run.)  The white line shows the second step that the tackle will take.

The second step of the covered ilineman is into the "cylinder" of the defender.  If the defender had stepped forward, this tackle would be blocking on the shoulder of the defender and seeking to carry him away from the play.  If the defender stepped sideways, the tackle would engage and continue their momentum outward.  In either case, he avoids taking a full-on charge by the defender.

The uncovered defender takes his first step obliquely - seeking to penetrate into the defensive backfield.  The key is the star:  the uncovered defender looks to block a spot immediately behind the leg of the defensive end in this picture.  It doesn't matter if the end stays anywhere near this spot: the guard will block there.

With his second step, the uncovered lineman blocks straight toward that star.  In this case, if the defender is in the area, he will support the tackle by double-teaming the end in the process.  But he will not focus his attention onto the defensive end.  The double-team block occurs merely becuase the end is in the way of his block on the star.

This is also insurance for the tackle.  If the defensive end happens to charge straight toward the tackle's initial step, the guard's second step allows him to support the tackle long enough to (hopefully) allow the tackle to win the battle and seal up the block.  But it's all designed to get the guard to the star, where he will then make his next decision.

Let's see the full play in action:

Going back to that 3-4 diagram from above, we now see the effective first step of everybody of the interior of the formation.  (Note that I brought the outside lineback up to the line near the tight end; this creates more of a 4-3 line weighted toward the anticipated direction of the run, which is customary for a 3-4 defense.)  See how the covered players first stepped laterally while the uncovered players step obliquely.  The tight end even makes a bit of a mistake stepping forward (perhaps the linebacker shifted late); it's not unrecoverable so long as he maintains his principles.  The halfback receives the ball from the quarterback - either by pitch or by handoff.  The handoff has the added advantage of a play action bootleg, but we're only looking at the running play for now, so assume everybody's thinking "run".)

The first step simply establishes position; the second step is where the battle is won.

With the second step, the covered linemen engage and follow the direction that the defender's position suggests.  The center and left tackle here will try to drive their defenders laterally along the line of scrimmage.  The right tackle will seal the outside edge and keep his man in the gap that he initially tried to jump into.  The guards block toward their spots and offer assistance if it's convenient.  The tight end blocks like the right tackle in this case because of the defender's position. So far, everybody ignores the other linebackers.

At this point in time, the halfback has made his decision and commits entirely to one running option.  Here, because of the outside contain on the right end of the line, he will sweep to the outside.  The blockers are in ideal position to control the end of the lline and the runner should be able to turn a 4-6 yard gain.

So long as the right tackle and tight end stay latched onto the shoulder of their defenders, the interior of the defense has lost on this play.  The guards are now ready to read the linebackers and try to block them as they pursue (though it'll probably fail on the outside sweep).  The receivers are now blocking their coverage as well.

The outside rush is good for a modest gain, but is not the home run for a zone run.  In reality, the offense is hoping that the defense has committed to stopping the outside rush by sliding with the play.  This opens up the cutback, which can utterly decimate a defensive interior.  Watch what happens when the defense pursues the sweep:

Here, the defenders have slid outside to prevent the sweep; the halfback then picks the best cutback lane he can find and runs toward it.  He must commit to it; the offense cannot hold open a hole for very long.  Indeed the very existence of the hole depends on the halfback's choice.  The dashed line is the least desirable lane, though it could be an option if the defensive end had rush inward rather than outward.

Note the leverage positions of the covered linemen - especially the center and right tackle.  The right tackle will drive his defender along the line of scrimmage.  He knows he doesn't have the outside contained, but he trusts the runner to see that and take a different option.  The center is locked onto the nose tackle but has support from the guard.  When the halfback cuts back, the defenders instinctively follow the cut and try to chase.

When the defenders try to change their direction, they give up momentum in the blocking battles, and the linemen can suddenly shove the defenders - usually straight to the ground.  The two guards are then free to pursue the linebackers (who are running toward the potential cutback lanes).  If the rusher chooses the middle lane:

By this time, the guards will have helped the center and right tackle take the nose tackle and defensive end to the ground.  (Sometimes this is accomplished by a cut block, which is a huge subject in itself.)  The guards are now at their zone and focus their attention on the charging linebackers.  The halfback will most likely hurdle the nose tackle and trust the guards to occupy the middle linebacker.  This hole will not last long; if the runner waits, the linebackers will be able to slide far enough into the holes to cut the space down, and the outer linebacker will be able to catch up to the play.

Let's change the situation a bit to encourage the runner toward the far gap.  Suppose the far defensive end chose an outside rush on the play:

With this move, the far gap becomes an option.  Once the end chooses an outside rush, the left tackle largely ignores him.  (He'll be too far away from the play to be useful if the running back does his job.)  The tackle is now uncovered and zone blocks up to the outside linebacker.  The guards also zone block toward their presnap read points and prepare for the middle linebackers.

But what's important now is that the running back aims for where the hole will be.

The halfback must remember that the line is flowing toward his right.  By the time he gets to the hole, the players will have shifted.  If he runs where the hole appears to be right now, he'll run straight toward the outer linebacker.  Even though that linebacker will be blocked by the tackle, the misstep will slow the runner down enough for the defensive end to recover.  Instead, he runs more straightly upfield and trusts his blockers.

Taking the next step:

As the halfback approaches the line, the flow carries the nose tackle away from him.  The left tackle occupies the outside linebacker and the left guard takes on the inside linebacker.  This is why quick linemen are key in a zone scheme; if they can block linebackers successfully, this play may go 10 to 15 yards (or more, if the safeties are out of position).

The key is the lateral motion that is created.  If the defensive linemen charge forward, the outer edge gets sealed and the runner usually gets a modest gain.  If they flow to the outside, they lose penetration and their momentum puts them out of position for the cutback.  The quicker the running back makes his cut, the more dramatic the effect.

Live Example

The Denver Broncos under Shanahan were the best zone runners in the business.  NFL Films has a great live example of the scheme, presented by Brian Billick.  (Opens in a new window.)  Billick spends most of the time talking about the running back, but if you watch carefully you can see the zone blocking as outlined above.

I hope this gives you something to look for a the Orange and White game, as well as during the fall.  When run properly, a cutback on a zone stretch causes the defenders to fall like bowling pins.