To effectively defend in the NFL, coaches must routinely craft strategies that add an additional player to the box as a method for stopping the run. In theory, this would put eight defenders in the box against two-back sets and seven defenders in the box against one-back formations. With the quarterback ignored as a runner, the extra defender is often the free hitter in the alley. Against jumbo sets, however, the numerical advantage is essentially nullified, with the split end or flanker replaced by an additional tight end or offensive tackle positioned at the end of the line. Part of this is due to the alignment of the wide receiver. Most defensive coordinators are reluctant to leave a cornerback on an island (without safety help) against a talented pass catcher; thus, at least one defender is pulled away from the box. In addition, the presence of an extra offensive lineman positioned at the tight end spot creates a significant size and weight advantage at the point of attack.