Understanding Bill Callahan’s Zone Blocking Scheme: Dallas Cowboys O-line Profile


Ever since Bill Callahan’s arrival in Dallas, fans and media alike, proclaimed his offensive prowess (and more specifically his prowess to the O-Line). After witnessing a season in which the Cowboys run-game ranked 31st in the league, you’re probably asking, if he’s such an offensive line genius, why is the Cowboys offensive line so terrible? That’s a perfectly reasonable query we plan to answer over the next couple days.

Yesterday we evaluated the Offensive Line’s 2012 performance in Part 1. Check it out here if you haven’t seen it already. Today in Part 2 we are going to explain Bill Callahan’s Zone Blocking Scheme (ZBS) and why the Cowboys have hope for improvement in 2013.

Dec 2, 2012; Arlington, TX, USA; Dallas Cowboys offensive line coach Bill Callahan talks with tackle Doug Free (68) during the game against the Philadelphia Eagles at Cowboys Stadium. The Cowboys beat the Eagles 38-33. Mandatory Credit: Tim Heitman-USA TODAY Sports

The Change

Over the years, the Cowboys have relied almost primarily on a Man Blocking Scheme (MBS) on the offensive line. The only time in recent memory they strayed from MBS was Bruce Coslet’s brief tenure with the ‘Boys (which had an ending similar to that of Old Yeller).

In recent years they cut their Super Bowl winning position coach along with that old Pro Bowl Line of Flozell Adams, Leonard Davis, Marc Colombo, Andre Gurode, and Kyle Kosier. Those gentlemen were good but seemed to consistently fade towards the end of every season. They were the best in the NFL in week 1 but walking turnstiles by week 17. A change was needed. A big change. And that change was more than just a coach. It was more than just players. It was all of that PLUS an entire blocking scheme change.

Regardless of how their zone blocking experiment ended before, they are at it again.

This isn’t college football where a team like Alabama can just field players who are so athletically superior to their competition, they can beat their opponents 1 on 1 every time. This isn’t even the early 90’s NFL where free agency and the salary cap don’t inhibit a team like the Cowboys from building and keeping an All-Star O-Line. In today’s NFL teams are so evenly matched the strategy of just “beating the guy in front of you” (as Bill Parcells would often say), doesn’t work anymore. Mismatches and deception are needed. And that is where Zone Blocking comes in…

Dec 2, 2012; Arlington, TX, USA; Dallas Cowboys tackle Tyron Smith (77) prepares to block Philadelphia Eagles defensive end Trent Cole (58) during the game at Cowboys Stadium. The Cowboys beat the Eagles 38-33. Mandatory Credit: Tim Heitman-USA TODAY Sports

Zone Blocking in the Running Game

In the running game a ZBS is ideal for a team with quick athletic linemen. It’s no longer about just blocking the guy in front of you and many times requires you to block the guy in front of someone else.

The first task of an offensive lineman is to identify whether he is “covered” or “uncovered”. This will determine exactly who the offensive lineman will block. Whether an offensive lineman is covered or not is based on the direction of the play and the technique (or positioning) of the defensive linemen.

For instance, if the play is going left and the center (Travis Frederick) has a defender lined up on his left shoulder (the direction of the play) he is “covered”. So in this case when the play begins Frederick will block this DT lined up over his left shoulder. Easy enough, right?

Dec 16, 2012; Arlington, TX, USA; Pittsburgh Steelers defensive end Brett Keisel (99) tackles Dallas Cowboys running back DeMarco Murray (29) at Cowboys Stadium. Mandatory Credit: Matthew Emmons-USA TODAY Sports

Here’s the twist. If that same DT lines up directly over Travis Fredericks head in the zero technique (rather than the left shoulder) the assignment can change and just because he’s now 8 inches to the right, he is no longer Fredericks blocking assignment. With 1 DT in zero technique, now say a second defensive lineman is lined up directly over the left Guard.  Travis Frederick would be responsible to block that player over the left guard  rather than the player directly over him. It sounds strange but think of it like this:

The offensive line is required to flow in the direction the ball is moving. Who they block depends on the positioning of the defense. So the offense could run the exact same running play two times in a row and the offensive linemen could block entirely different players both times. That is because the defense dictates how they will be blocked and by whom.

What this does is it opens multiple running lanes as the play develops. The runner is required to run patiently and find the right lane to burst through. Often times a cutback lane becomes available because of over-pursuit and cunning offensive linemen using a defenders speed and aggressiveness against him.

In 2012 the Dallas Cowboys were frequently beaten at the point of contact. 8 out of 10 times the Cowboys line was manhandled by their opponent across from them. Playing a ZBS can tip the balance back in the offenses favor if executed properly because it doesn’t relay solely upon strength.

Dec 16, 2012; Arlington, TX, USA; Dallas Cowboys quarterback Tony Romo (9) throws in the pocket as center Ryan Cook (63) blocks against Pittsburgh Steelers nose tackle Casey Hampton (98) at Cowboys Stadium. Mandatory Credit: Matthew Emmons-USA TODAY Sports

Zone Blocking against the Blitz

Zone Blocking is often times more effective against the blitz too. In a typical Man Blocking Scheme, running a stunt or blitz can be extremely difficult to handle. Last season defenses knew this so they frequently blitzed and stunted (up the middle mostly) against the Cowboys. With a ZBS even the most exotic blitzes can be effectively handled. The offensive lineman is responsible for blocking a zone and if two players blitz through the zone it no longer ends in certain tragedy.

As long as the ZBS is executed correctly it can succeed. TE’s are required to double team, seal the edge on the backside, and get downfield to block the next level. ZBS is ideal for a 2 TE offense because of the versatility they provide. Everyone’s assignment is based on what the defense does so it’s inevitably adaptable. Pre-snap it looks the exact same as a MBS so the defense isn’t sure what to expect until it’s already happening.


A change of scheme on the offensive line like this is substantial. It’s one of the hardest things to do. It requires a change in personnel, running style, and exactly one metric crap-load of practice and application to make it work. New Offensive Line Assistant Frank Pollack brings his expertise to the table to help speed this transition. Pollack has experience with the ZBS from his days in Oakland and Houston. Callahan has experience with both MBS and ZBS and began to install a little ZBS last season. This season it’s expected the team will be primarily a ZBS with hints of Man blocking to keep the defense honest.

June 11, 2013; Irving, TX, USA; Dallas Cowboys center Travis Frederick (70) during minicamp at Dallas Cowboys Headquarters. Mandatory Credit: Matthew Emmons-USA TODAY Sports

Most teams in today’s NFL run a combination of ZBS and MBS. Like most things in the NFL, if your opponent knows you always run a MBS they can easily find ways to take advantage (typically by stunting and blitzing). Likewise if you run all ZBS, opponents will expect the double teams and adjust accordingly. Trickery and deceit are no longer solely for defenses now. Offensive linemen use it too.

Dallas’ rookie center Travis Frederick has great experience in a ZBS playing at Wisconsin. He has experience calling the blocking assignments for his teammates and executing the assignments himself. He was truly a reach in the first round but when considering his importance on this defensive transition, the Cowboys didn’t want to risk losing him.

Frederick will make this transition work for the Dallas Cowboys. The obvious physical short-comings of the personnel are no longer fatal. This takes practice to successfully implement so staying healthy through training camp is a must. But with this new transition the Cowboys will have hope for improvement in 2013.

Thursday we will wrap up in Part 3 by breaking down the offensive line camp battles and who we can expect to see starting in 2013.

Do you have questions or comments regarding Dallas area sports? Email Reid at permaximum@hotmail.com. You may be included in the next weekly mailbag. Follow Reid on twitter @ReidDHanson