There's a lot to cover, so I won't get cute. Seahawks fans understand the stretch play. It is a fundamental play in Greg Knapp's offense. It is a good play: Simple, and therefore with a short learning curve, quick-developing and also able to be run against about any type of defense. The inherent weakness of the stretch play is backside pursuit. The trailing tackle does not block the opposing defender. The running back is entrusted to pick, get to and through the hole fast enough to nullify that defender.
The Arizona Cardinals have invested heavily into their defensive line. That is typically the smartest method to developing an effective 3-4. Linemen have long careers and long peaks, and good defensive linemen make the linebackers around them play better. With its good size, power and athleticism in the middle, running backs typically have to elongate their routes to find a hole and that allows Arizona to be the best team in football at ‘stuffing' the run. Rushers get caught in the blocks, not allowed to build up speed before entering the hole and slow enough and indecisive enough to allow the Cardinals form-tackling linebackers and secondary to swarm.
The Cardinals lack good team speed. Their linebacker corps is mostly constructed of system correct retreads. Julius Jones has had trouble getting into and through his hole without being chased down, but with the exception of the Jaguars, he has faced teams with quick, agile linebackers. The best way to attack a team that freezes the middle is to attack the edges, keep its big bodies moving and simply outrun the backside pursuit. It won't work without execution. In the following series of posts, I will explain each step of execution required for Seattle to effectively run this vital play.