The Houston Texans have one of the league’s most potent offenses because of their ability to attack defenses through the air with the passing game and on the ground with the running game. The passing game is led by quarterback Matt Schaub and wide receiver Andre Johnson while the running game is led mainly by running back Arian Foster. Foster was an undrafted free agent coming out of the University of Tennessee and was signed to a contract with the Houston Texans in 2009. He contributed in his rookie season with 257 yards on 54 carries to go with three touchdowns, but his real success came in 2010, when he was announced as the starting running back.

Since the announcement, Foster has ripped through the NFL with long runs and multiple big rushing games. His performances against the Colts in Week 1 (231 yards) and the Jaguars in Week 17 (180 yards) are most notable. However, one has to wonder how a running back this talented went undrafted. Better yet, how has this undrafted running back found success in the NFL so early in his career?

The answer is the Texans’ offensive line and their use of offensive rush concepts, known as outside and inside zone. The Texans’ running game was built on zone blocking originally implemented by line guru Alex Gibbs. Gibbs was viewed as one of the best offensive line coaches in the NFL prior to his abrupt retirement in 2010. He shared his teachings at coaching clinics, as can be seen at Brophyfootball.

Zone blocking can be defined as offensive lineman who are assigned an area to block and then pick up any defender that comes into their designated area. Zone blocking also has two rules, as explained by Chris Brown of covered and uncovered rules. If an offensive lineman is covered by a defensive player, head up or by shade, the offensive lineman is responsible for blocking the player in front of him. However, if an offensive lineman is uncovered, he is to help the playside offensive lineman block the defensive lineman by forming a combo block and then peel off into the second level to take on the linebackers. When blocking the defensive line, the offensive line wants to keep their head in the playside direction as well as gain leverage in the same direction to get the defense flowing all in one direction. Once the defense is flowing to the playside, they will open up holes in their front for the running back to run through, which leads me to the run concepts of inside and outside zone.

The inside zone run concept is one of the most interesting because of its great success in football at all levels. It is based on the offensive line blocking playside after taking a step sideways (known as a “lateral step”) to get an angle on defenses flowing playside and out-leverage them. Once the offensive line has taken that lateral step, they want to get their heads on the outside of the defender to get them moving in the same direction, and then reach to get their hands on the defenders.

The running back is also key here because he is the one required to make the cuts and find the holes. In this case, Arian Foster targets the outside leg or hip of the guard. Once the running back takes his first two steps to receive the ball, his third step is a read step which is when he decides where he wants to go with the ball. Once he spots a lane to run through, he wants to make one cut and press the hole. Below is an example of Arian Foster in a Week 17 matchup against the Jaguars finding a hole on the inside zone call by head coach and play-caller Gary Kubiak.

As can be seen above, the center is the only uncovered offensive lineman, which means his job is to help the playside offensive lineman (74) on the play. The remaining offensive lineman are covered head up or shaded by a defensive lineman.

In this next image, the development of the play is shown. After taking a lateral step, the offensive linemen all block in one direction. The three offensive lineman to the left (left tackle, guard and center) are all blocking with outside leverage, meaning their helmets are outside of the defenders. The center (55) is combo blocking with the left guard because he was uncovered. The running back, Foster, received the ball on his third step and is going through his keys.


This is where the offensive linemen really start moving the defenders. The left tackle (76) has control of the defensive end and has moved him two-to-three yards from his original alignment, while the left guard (74) has his head outside of the defender and has the leverage. The center has peeled off the combo block with the left guard and is working his way to the second level on the nearby linebacker. The backside guard and tackle have lost the leverage against the stunting defensive tackle, but it’s already too late for the defensive tackle to make a play on the ball carrier because the ball carrier has found the lane and is getting ready to hit it. The flowing linebackers are all out of position, which leaves the backside of the formation open for the running back to run freely.

The next play is the outside zone, a concept similar to the inside zone except that the running back targets the outside hip or leg of the offensive tackle on the playside. The offensive linemen still have the same covered/uncovered rules and goal of getting the defense flowing in one direction. Below is an example of the Texans running outside zone against the Jaguars.

In the image above, the center is the uncovered offensive lineman, and thus has the responsibility of helping the playside (right) guard, as seen in the image below.

The offensive line takes a sideways step and drives the defenders playside. The right tackle is blocking the defensive end while the right guard and center are combo blocking the defensive tackle. Meanwhile, on the backside of the play, the left guard and tackle are man blocking, which is a call made by the center.

In this last image, the back has received the ball and is targeting the outside hip of the right tackle. The right tackle does a good job playing with leverage, which allows Foster to end up cutting inside the right tackle, which he is free to do, because of the hole that opened up. The center ends up taking the defensive tackle one-on-one after the right guard peels off to get to the second level and take out the linebacker.

Zone blocking has been around for decades, but Gibbs’ teachings have taken it to a whole new level and have impacted teams throughout the NFL and other levels directly and indirectly, and they’re especially noticeable in the Houston Texans’ running game.

Additional reading: Inside Zone Outside Zone by Bill Mountjoy