One position that has undergone a great deal of development in Indianapolis is the defensive tackle position.
In 2007 and 2008 the Colts had the smallest defensive tackle rotation in the NFL. By the smallest, it was not just a little smaller, it was 50 or more pounds lighter than the second lightest defensive tackle group in the league. The 2009 season saw that change.
While the Colts may still field the lightest defensive tackles in the NFL, the difference between Antonio Johnson, Daniel Muir, Fili Moala, Mitch King, and Eric Foster from the rest of the league is closer than the Colts have been since the 2005 and 2006 seasons, when players like Booger McFarland and Corey Simon were on the roster.
The importance of the increase in the size of the Colts defensive tackles cannot be overstated.
For years the team had anemic run defense, primarily due to interior runs and undersized defensive tackles getting blown off of the line. In 2009, the Colts were much stouter against inside runs, even stepping up as one of the toughest teams in the league in short-yardage and goal line running situations. Part of the reason for this importance, outside of the improvements already discussed, is that the Colts defensive scheme requires two different kinds of players with different responsibilities to function as intended.
In the Colts scheme, defensive line coach John Teerlinck trains all of his defensive linemen to play the run on the way to the quarterback. This penetrating style of run defense increases the likelihood that opponents' running backs will have to bounce outside, move laterally, or get stopped in the hole. In a defense predicated first on speed, the more disruption that occurs behind the line, against the run or the pass, the more likely it becomes that the Colts speedy defenders produce tackles for a loss, deflect passes, pressure the quarterback, or generate sacks.
One way the defensive tackles are designed to aid in getting pressure is by fielding one defensive tackle with "nose tackle" responsibilities and another "under tackle" whose primary responsibility is to slide off of blocks and get penetration. Nose tackles are typically referred to as space eaters or run stuffers. Their primary job is to hold the line, keep the offensive line from getting a push up the middle, and demand as many double teams as possible.
The under tackles are typically smaller, faster, and more concerned with penetrating not "through" offensive linemen but around them. They will often focus on using their speed and hands to "swim" past offensive linemen to collapse the pocket or disrupt the backfield.
In prior years, the Colts did not have a "true" nose tackle. They had two players more suited to the under tackle role and the result was that offensive linemen could choose which direction they wanted to run up the middle and force the tackles out, slip off of those blocks to hit linebackers, and essentially punch the defense in the mouth.
Now the Colts have three defensive tackles that are heavier than 300 pounds: Antonio Johnson, Daniel Muir, and Fili Moala. This year the Colts are using a primary rotation with these three players, making it far more difficult for opponents to destroy the Colts defense on the ground.
Mitch King, Eric Foster, and Ricardo Mathews are smaller but typically only see the field during pure passing situations and serve primarily as pass rushers.
It is often said that defensive tackle is one of the most difficult positions to learn in professional football. The reason for this is varied. First, defensive tackles are not "straight ahead" players who simply get one assignment and have to play that role. These big guys are required to get penetration while not getting blown off of the ball, have to learn when they will play the hole directly in front of them, when to line up offset, and when they will "stunt" by quickly moving behind one another to plug a different hole.
Beyond that, defensive tackles suffer from one of the biggest size and skill wake-ups in the game. A great running back or wide receiver can excel in the NFL by using their God-given talents, such as speed, disciplined routes, and hands. Defensive tackles have to line up across players who will have their hands on them immediately and have to learn how to face a huge talent and size increase from their college days. They are lining up against five men on the offensive line who are the best of the best they ever faced while in college.
As a result, winning in the trenches, getting push, trying to slide off of larger, stronger, and faster guys across all of the line positions is not easy. The "old tricks" do not work anymore and their "size advantage" against college competition, in many cases, disappears. It is what makes players who are successful in their first years like Ed Johnson so rare. It just does not happen at defensive tackle for even the highest rated, top draft picks most years. It takes time, and is part of the reason why 2009 second round selection Fili Moala had so little impact in his rookie season.
Now that he is acclimated to the NFL speed, size, and scheme differences, he can begin making meaningful progress. He has displayed this progress already, playing the best game of his career against the Giants in Week 2.
Beyond the developmental challenges, defensive tackles also suffer a great deal from a relatively shallow talent differential once the light clicks. Additionally, players enter the NFL as young men who have not fully developed. As such, a lot of players like Ed Johnson, can turn into star defensive linemen due to their physical and athletic development as men. It makes picking future starting defensive tackles very difficult.
This year will see the defensive tackle position continue to develop on the Colts. Moala, Johnson, and Muir will be the largest steady rotation of defensive tackles the Colts have had in many years. The smaller defensive linemen will see much more time at defensive end. Keep your eye on the position, if opponents cannot run but there is no penetration or pressure on the quarterback, things may change again.