Traditionally, the left defensive end is the stouter, less pass rush-oriented compliment to the explosive right defensive end. Despite that, left defensive ends like Patrick Kerney, Julius Peppers, Jared Allen and Aaron Kampman are consistently among the top sack producers in the NFL. Some of that might be a simple, meaningless confluence of talent at the right defensive end position, not indicative of any larger trend. But some it might also be explained by the changing nature of the tight end position in the modern NFL.
Blitz: A defensive play that involves a non-lineman rushing the passer.
Spread Offense: An offensive strategy that emphasizes shotgun snaps, 3-5 wide receiver sets and a general emphasis on spreading the defense horizontally across the line of scrimmage. The most rudimentary spread offense is credited to Glenn Ellison.
Strong Side: The side the tight end aligns on. Commonly, the right offensive side.
Tight End: A position along the offensive line just to outside of the tackle. Also, players who typically play that position.
Weak Side: The side the tight end does not align on.
Zone: A type of pass coverage that involves a defender not defending a specific offensive player, but an of the field.
Zone Blitz: A type of blitz invented by Dick LeBeau where at least one linemen drops into coverage.
Back in the days of the Flying V, the tight end was little more than an extension of the offensive line. Blocking has stayed an essential duty of the tight end until recently. More and more “tight ends” do not play the tight end position. Players like Dallas Clark and Antonio Gates are as much slot receivers as tight ends. More so. Despite a de-emphasis on blocking by tight ends, most teams still put their inferior pass blocking offensive tackle on the right side. Therefore, left defensive ends typically face inferior competition.
The left defensive end is less likely to be run at. In each of the last three seasons, teams have run to the left more often than the right. Against the run, a left defensive end may be asked to provide outside containment. Outside containment essentially involves running around the right “C” gap and preventing the rusher from breaking outside. This is especially common when the right defensive end faces a “weak” formation: a tackle without an accompanying tight end. Against a “strong” formation, a defensive end might be asked to force a double team, keeping the tight end from blocking the accompanying strong side linebacker. In this two gap assignment, the defensive end must hold the point and occupy the blockers. Playing the strong side, left defensive ends are also more likely to drop into a zone on a zone blitz, theoretically covering the tight end.
Prototypical Left Defensive End: Reggie White