Since Jason Garrett has been coaching for the Dallas Cowboys, the team has used a version of the Air Coryell as their dominant offensive philosophy. The other day we broke down what exactly the Air Coryell is and how Garrett’s days as a player for America’s Team influenced his preference for the scheme.

But while the recurring narrative is that Garrett’s offense has become stale and predictable - which it definitely did from a playcalling standpoint under Scott Linehan - the reality is that Garrett and others have made tweaks to the Air Coryell scheme over time and blended in elements of other offensive philosophies.

This piece will attempt to track all of those changes, or at least as many as can be found from the outside. But first, let’s start at the beginning of Garrett’s tenure in Dallas. He was hired to be the new offensive coordinator in 2007, coinciding with the hiring of Wade Phillips as the head coach. Phillips replaced Bill Parcells, who had run his variant of the Erhardt-Perkins offense.

Garrett took over the offense, which had ranked fifth in yards and fourth in scoring the year prior. With Tony Romo entering his first full season as the starting quarterback, Garrett switched up the offense to his version of the Air Coryell, which was very much like the Air Coryell offense that Norv Turner ran for Dallas in the 1990’s but with one big change.

When Turner took over the Cowboys offense in 1991, he came from the Rams, where offensive coordinator Ernie Zampese - a direct disciple of Don Coryell - had been running the Air Coryell. However, Zampese had made one alteration with the blocking scheme: whereas Coryell had used a lot of man blocking schemes that relied on big maulers on the offensive line going straight ahead, Zampese used a slightly different blocking scheme that was taught by his offensive line coach at the time, Hudson Houck. While still a man blocking scheme, Houck asked his linemen to do more types of blocks, using double-teams at the point of attack and pulling blockers and performing kick-out blocks.

So when Turner arrived in Dallas, he continued to use this blocking scheme with offensive line coach Tony Wise. In 1993, Turner’s last year before becoming the Redskins head coach, Houck joined him and continued his type of man blocking scheme there. While the Cowboys generally had linemen that were of the big mauler body type during this generation, Houck took advantage of the full arsenal of blocking techniques that allowed players like Larry Allen and Erik Williams to channel their strength and aggression into a dominant unit.

However, when Garrett was hired in 2007, one of the few holdovers from Parcells’ staff was Tony Sparano, who was the assistant head coach and offensive line coach. Sparano brought more of that mauling, physical style of blocking, which had similarities and differences with Garrett’s preference for Turner’s diverse man blocking Air Coryell. From watching game film of the Cowboys throughout the 2007 season, there seems to be a solid mix of both approaches, and while the offense was very good in the 2007 season, they played their worst football at the end of the year when they averaged under 13 points a game and went 2-2, including the playoff loss to the Giants. The inconsistent technique in the offensive line was a big reason why, as opposing defenses knew how to better attack the protections’ weak points by that point in the year. This kind of dysfunctional dichotomy would rear its head again in 2018.

However, Garrett’s offense on the whole was fantastic in 2007. They actually improved as a unit from the 2006 season, rising up to third in yards and second in scoring. Romo made the Pro Bowl, and the running back tandem of Marion Barber and Julius Jones was effective, combining for 1,563 rushing yards and 12 touchdowns. But Garrett wanted to make a change to his blocking scheme, it seemed.

Sparano got hired away as the Miami Dolphins’ new head coach, and Dallas brought in none other than Houck himself. Garrett knew Houck from his time spent in Miami on Nick Saban’s staff, and of course from when Houck coached the Cowboys previously. So as the Cowboys entered the 2008 season they adopted the blocking scheme that Turner had used in the 90’s.

For a while, it worked really well. The Cowboys entered December with an 8-4 record and sitting in second place in the NFC East with an offense that had been averaging 25 points per game, which ranked tenth in the NFL. But just like the previous season, Dallas faltered late and lost three of their final four games, including being blown out 44-6 in the season finale against the Eagles, which ousted any playoff hopes. Dallas finished 13th in yards and 18th in scoring.

This caused the Cowboys, and most notably Garrett, to do some introspection. They ended up letting go of Terrell Owens, entering the 2009 season with (brace for it) Roy Williams as their top receiver after trading for him during the 2008 season. Garrett also changed up the way he coordinated the running game. For two years, Garrett had used Barber as his main back with Jones - first Julius and then Felix - as a complement. But after the Cowboys’ December downward spiral coincided with losing both Barber and Jones to injury, Garrett began to use more of a running-back-by-committee approach between Barber, Jones, and Tashard Choice.

Garrett also started to make his offense a lot more pass heavy than before, which required asking more of Romo. Prior to the 2009 season, Romo was averaging 29 pass attempts per game for his career. In 2009, Romo averaged nearly 35 pass attempts per game. He also set a then career best for passing yards with 4,483 while increasing his yards per attempt from 7.7 to 8.2. But the biggest change for Romo in 2009 was that he was asked to do more pre-snap reads of the defense.

This began a trend that Romo became comfortable with, where he usually wouldn’t snap the ball until there were roughly five seconds or less on the play clock. This tactic was supposed to make defenses jumpy and force them to reveal their coverages and blitzes better, and it mostly worked. Something that Garrett did to help Romo with the pre-snap reads was a significant use of pre-snap motion. When I went back and watched the 2009 Cowboys offense, I was shocked at just how much motion Garrett used. It felt like watching the Rams or Chiefs today, and it’s weird and frustrating that the team was so ahead of its time back then but wasn’t able to do any of it the last few seasons.

Anyway, Garrett’s heavy use of pre-snap motion and the running back rotation worked wonders. Garrett also made heavy use of play-action bootleg plays that targeted running backs and tight ends, and these plays usually put up big yards. It also helped that Miles Austin emerged as a legitimate receiving threat midway through 2009 as well, and the Cowboys finished with the second best offense in the NFL that powered them to an 11-5 finish and their first playoff victory since 1996. It seemed that Garrett had found the perfect form of his offense in year three, and the Cowboys were Super Bowl favorites entering 2010.

Of course, we all know how that went. A slow start and a broken Tony Romo collarbone led to Phillips being fired after a 1-7 start and Garrett’s ascent to head coach. Garrett continued to call plays as well, and led the team to a 5-3 finish to place the Cowboys at 6-10 overall. For what it’s worth, Garrett’s offense was still a top ten unit: they ranked seventh in yards and scoring, sixth in passing (with Jon Kitna at quarterback, no less), and 16th in rushing.

Still, that set in motion a sprawling rebuild under Garrett. Over the next three years, Dallas significantly revamped their offensive line and completely switched defensive schemes, going back to a 4-3 scheme. That scheme change brought coaching changes, most notably Rod Marinelli, but the offensive line rebuild also saw a key coaching change: Bill Callahan.

After the 2011 season, Houck retired from coaching. The Cowboys eventually settled on Bill Callahan, who was the assistant head coach and offensive line coach for the Jets at the time. However, since Callahan couldn’t just make a lateral move to Dallas, the Cowboys named him offensive coordinator and offensive line coach, even though Garrett still called the plays. But after the 2012 season, Callahan began calling plays in order for Garrett to focus more on game management.

Up until this point, Garrett had been running more or less the same type of offense he perfected in 2009, albeit with less impressive results due to their rebuild. But Callahan brought in two big changes that he had experience with from his days with the Jets. The most notable one was his shift from Houck’s diverse man blocking scheme to a zone blocking scheme that Callahan preferred. This change helped speed along the Cowboys’ rebuilding project on their line, as Tyron Smith became a Pro Bowler for the first time in 2013 and rookie Travis Frederick was named to the PFWA All-Rookie team.

The other change Callahan brought is often overlooked, but it could be the difference maker for new coordinator Kellen Moore. While in New York, Callahan worked closely with offensive coordinator Brian Schottenheimer, whose offensive scheme was derived from his father, Marty Schottenheimer, and was effectively a mix of the Air Coryell and Erhardt-Perkins. It combined the power running of the Air Coryell and its preference for well timed deep shots with clearer, more concise language that made it easier for quicker playcalls. BTB’s own Rabblerousr broke it down in more depth back in 2013:

As I understand, Erhardt/Perkins is more about terminology than actual plays. Much shorter terminology for play calling means quicker communication at the line, more time to assess the defense and adjust, or snap quickly to catch the defense unready, and much less last second snaps as the clock winds to 0 (especially with Frederick making the line calls)

Callahan implemented this change in order to speed up the Cowboys’ offense and take pressure off of Romo, who had been spending too much time being chased by defensive linemen while waiting for a receiver to open up downfield. It didn’t quite work out, as Dallas ranked 16th in total offense, and there seemed to be tensions between Garrett and Callahan over playcalling.

This led to the team bringing in Scott Linehan as the passing game coordinator for the 2014 season, and while Callahan still held the title of offensive coordinator, it was Linehan - a close friend of Garrett’s from their days on Saban’s Miami staff - who called plays. He still operated under the implementations of the Erhardt-Perkins system Callahan brought, but seemed to have a better command of calling plays.

That didn’t last long. Although Linehan engineered good offenses in 2014 and 2016, he struggled to adapt to changing personnel in 2017 and 2018, which ultimately led to his ousting. Linehan was also hampered by the departure of Callahan, who got out of dodge as soon as he could with a chip on his shoulder. Callahan’s top assistant in Dallas, Frank Pollack, was promoted to offensive line coach in order to bring continuity to the line. However, the line regressed under Pollack and he was let go after the 2017 season.

This brought in another schematic change with Paul Alexander, who used a mix of blocking schemes that featured a unique teaching style. The big issue is that it asked the linemen to tone back on the aggressiveness that both Houck and Callahan had previously emphasized. As a result, the offensive line struggled mightily, and Alexander didn’t last a full season. Marc Colombo brought the aggression back, and some of the old-school techniques the players were used to and saw improvements, but it wasn’t enough to save Linehan from the same fate as Alexander.

Now comes Kellen Moore, with one year of coaching experience, who’s spent nearly his entire professional football career with Linehan. However, it seems that Moore is going to bring some major changes to this offense, which would be welcome, although it wouldn’t be the first time that’s happened under Garrett. In the follow-up, I’ll break down how Moore’s offense might fit in with what the established order in Dallas.