When Tom Landry invented the modern 4-3, his intention was for the front four linemen to control the opposing offensive linemen thus freeing the linebackers to make plays. In the modern NFL, the right defensive tackle position best embodies Landry’s original intention. Unlike its fellow line mates, a right defensive tackle can be valuable without recording tackles, pressures or sacks. In fact, the collective contributions of the right defensive end and left defensive tackle are often the best indication of the quality of the right defensive tackle.
0-Tech: A defensive lineman who primarily plays across from the center. Also known as Nose, Nose Tackle or Nose Guard, especially in a 3-4 alignment.
1-Tech: A Defensive lineman who primarily plays across from the gap between the Center and (usually left) guard.
Double Team: Any time a single player is countered by two players from the opposite team.
Forced Double Team: Any time a single player forces a double team with his actions in that play, in preceding plays or by reputation.
One of the more prevalent misnomers in the modern NFL is the idea that a coach wishes his defensive linemen to "occupy" blockers. A blocker can be occupied jogging a defensive end ten yards past the line of scrimmage. That fails to help the defense, though. A defensive lineman must control the opposing opposing lineman or linemen. Be able hold ground when an offensive lineman attempts to move them away from an intended rushing lane. Be able to move the offensive lineman away from their fellow offensive linemen, creating pass rush or run stuffing lanes for their own linebackers or defensive backs.
An effective right defensive tackle can easily control a single blocker. By controlling an opposing guard or center, they can stifle rush lanes, collapse the pocket or create pass rush lanes for their linebackers or defensive backs. A great right defensive tackle can easily control two blockers, but that’s exceedingly rare. A good right defensive tackle forces the opposing team to consistently assign two blockers, usually the left guard and center, to block him. In this case, simply occupying the blockers is beneficial. That’s because if a right defensive tackle can occupy two blockers, it leaves the right defensive end, left defensive tackle and left defensive end single blocked—greatly improving their individual effectiveness.
It should be understood that this is a prototypical build. Some teams employ two defensive tackles that both do little more than occupy blockers. The 2007 Carolina Panthers, for instance. Others give the customary duties of the right defensive tackle to the left defensive tackle and visa versa. But most teams do or attempt to create a 4-3 in this mold. Even teams that employ a Tampa 2, the Chicago Bears for instance, usually have a larger, slower and stronger right defensive tackle and a faster, more agile, playmaking left defensive tackle.
A right defensive tackle may be assigned 1, 2 or 3 gaps. When a team runs a "single gap system", it means that in most defensive plays, their defensive linemen are assigned one gap, and rather than "read and react" or "control" that gap, they attempt to move through that gap and to the ball-carrier as quickly as possible. That is why these defenses are often referred to as "attacking". Controlling 3 gaps is exceedingly hard. It requires a player to be able fight off a double team between the two blockers or to the outside shoulder of either blocker. A player may be assigned 3 gaps in the case of a 3rd and long or 2nd and very long. That’s why, when a defensive tackle stops a surprise draw, it is an especially skillful display. A right defensive tackle is typically assigned two gaps. When playing the 0-tech, usually the gaps to the left or right of the center. When playing a 1-tech, usually the gap left of the center and the gap left of the left guard.
Right defensive tackles are referred to as run stuffers for their ability to stifle blockers and squash rush lanes, but their ability to occupy blockers, control blockers and free their line mates from double teams is equally important to the pass rush. The right defensive tackle is an unheralded position, but, with few exceptions, the achievements of the players around him are his achievements also.