It is pretty obvious what the Falcons want to do defensively, looking at the latest free agents they picked up to play defensive line in Atlanta. Paul Soliai and Tyson Jackson are both the huge, prototypical 3-4 defensive linemen Atlanta has been lacking. Bringing in two guys who fit the 3-4 scheme so perfectly really tips the hand of defensive coordinator Mike Nolan as to what kind of defense he wants to run.
What is a 3-4 defense?- The main difference between a 4-3 defense, which the Falcons have implemented for years, and the 3-4 which we presume they will run, is the number of defensive linemen and linebackers on the field at any given time. A 4-3 is four defensive linemen and three linebackers, and a 3-4 is three DLs backed by four LBs. The difference in the number of these position players means that there are subtle differences that might make a player better for one scheme over another. Obviously all of these football players need to be big, fast, and strong. But there are differences in how players combine these qualities to be suited for one playing style or another.
Since there are fewer defensive linemen on the field in a 3-4 they generally need to be bigger guys. Paul Soliai and Tyson Jackson are both much larger than the average defensive lineman, Soliai being 6’4” and more than 340lbs, Jackson is 6’4” and 300lbs. This added size is a function of the defensive lines responsibility to absorb the other team’s blockers. In a 3-4 there can be a difference in how the DLs and LBs take gap responsibility. The gaps refer to the spaces in between opposing offensive linemen before the snap and the gaps are called the A Gap, B Gap, or C Gap. The A Gap is in between the center and guard, the B Gap is between guard and tackle, C Gap is between the tackle and blocking tight end, D Gap is outside of the offensive formation. The gap control responsibility is schemed to either be a One Gap or Two Gap system. In a Two Gap system the defensive line is responsible for maintaining two of these gaps, and therefore two blockers, so that running plays are stopped and that linebackers are freed up to make plays in the opposing backfield. A One Gap system is more complicated because gap responsibility is split between the defensive line and the linebackers. This allows for a lot of versatility and is used my most teams. With the Falcons recent DL pickups the Falcons certainly have the beef up front to run a Two Gap system, something that has been missing in Atlanta for some time. Paul Soliai is the kind of dominating force in the middle that demands a double team, which is a kind of player Atlanta hasn’t had since Grady Jackson. Tyson is also the kind of player that must be game planned around by the opposing OLine. If I had to guess, given Mike Nolan’s ability to formulate hybrid game plans and his genius at alignment disguising, Atlanta will be a mix of One Gap and Two Gap.
I said earlier that the primary responsibility of the defensive line is to free up the linebacker to get into the offenses backfield to blow up a play. To do this the Dline has to draw double teams from the opposing blockers. If that doesn’t happen then the other team’s offensive linemen are clean to get past the line of scrimmage to block down field. Now that Atlanta has the kind of linemen that could consistently draw two blockers having versatile LBs is a necessity. The Falcons would hope to improve the pass rush from the linebacker position, not the defensive line. If you look at the career sack numbers of Soliai and Jackson, you would see that they barely combine for double digit sacks in their entire careers combined. That might sound alarming, but these two guys were not brought in to get the quarterback. They are here to stop the run and eat up opposing blockers.