In today’s NFL, quarterbacks routinely look to leave the pocket. This typically stresses the defense because it forces the secondary to cover for longer, but it is often forgotten that once a quarterback leaves the pocket defensive backs can become as physical as they like with the receivers they are covering. As soon as the opposing quarterback leaves the pocket against the Seahawks, Sherman is always looking to knock his assignment to the ground.
This may seem like a cheap move to the uninformed, but it is the smartest way to stop receivers from making big plays against you. The quickness of thought to recognize the scenario and his understanding of the rules is something that not every player possesses, even at this level.