
The "4-3" Defense
At this time, 26 NFL teams utilize a 4-3 defensive scheme. There are multiple coverage combinations that can be in play behind the front seven. Teams like the Indianapolis Colts and Tampa Bay Buccaneers use the 4-3 "Cover 2" system which is fast becoming the defense of choice in a lot of NFL cities.
Any 4-3 scheme, whether "Cover 2" or not is based on speed. Unlike the 3-4 system where the defensive linemen are tackles used to keep the linebackers free, the down linemen are the heart-and-soul of a 4-3 defense. There are similarities between the defenses though. Usually one of the two interior defensive tackles is a mammoth run stuffer that is used to clog the middle of the field. The other three defensive linemen provide the bulk of the pass rush for the defense. Teams that have a dominating front-four don't have to blitz to generate a pass rush and can utilize their three linebackers and four secondary members to defend the pass. Any 4-3 system uses smaller quicker defensive ends and tackles to aid in their pass rush. Developing a strong front four is critical in using any 4-3 scheme.
With the "Cover 2" scheme becoming so popular, people may ask, what exactly the "Cover 2" is. "Cover 2" is a pass-defense for teams with strong defensive linemen who don't require helping either rushing the passer or stuffing the run. It all starts with stopping the run with your down linemen because you don't have that eighth man in the box to help against the run.
By now, most everyone has heard of the term "Cover 2". Even though Tony Dungy made it a household name during his stint in Tampa Bay, the "Cover 2" was being played in the NFL long before Dungy was even a player in the league. It is one of the simplest alignments in football and it helps mask team liabilities in some areas. The basic principle is: Two half-field defenders and five guys underneath.
In "Cover 2", the two safeties are positioned deep and just outside the hash marks. Each safety is responsible for his deep half of the field. The underneath coverage consists of two corner backs responsible for jamming the wide receivers at the line of scrimmage. These cornerbacks fall into a zone coverage in the flat area. The three linebackers drop into a zone across the middle of the field, forming a line of defenders about 10 yards deep.
The basic idea of the defense is to eliminate the deep passing game by forcing teams to use their underneath or check down routes. The cornerbacks MUST get a good jam on the wide receivers to ensure proper defensive alignment.
This can be a great defensive system if the team has the personnel to utilize it. Finding the right defensive linemen for this scheme is one of the hardest things scouts and coaches have to do. The linemen must have a solid combination of size and quickness for this alignment to be successful.
Another popular coverage scheme is the "Cover 3" defense. In a "Cover 3" alignment one safety joins the two cornerbacks to form a three-deep alignment.
The other safety moves up and becomes the eighth man in the box. This gives the team one less underneath pass defender but does aid in stopping the run. Although this is one of the more conservative alignments on the defensive side of the ball, it is effective against both the run and the pass.