Reader Dave writes:
Could you address the different wide receiver positions: split end, flanker, and slot? How are their routes different? What makes certain guys suited to one position but not others? What roles do they play in the offense? I have read that in most West Coast offenses everything is designed to funnel balls to the flanker. Why?
First, the terms: a split end is a receiver on the line of scrimmage several yards from the five interior linemen. A flanker is aligned one or two yards off the line of scrimmage and split wide. A slot receiver is aligned between the main formation and another receiver. If he is inside the split end, he is off the line of scrimmage. If he is aligned inside the flanker, he is often (but not always) on the line. A receiver can also be "flexed," placing him on the line of scrimmage and four to six yards wide of the offensive tackle. This is usually a tight end's position, but in modern offenses wide receivers are often flexed. See the figure for some default positions.
Basic Wide Receiver Positions
I use these terms when explaining playbook diagrams, but they are really out of date. The terms are holdovers from T-formation offenses, in which the flanker was often one of the backs who reached the flanker position via presnap motion. Modern offenses use letter names for receivers: X and Z for the starting receivers, Y for the tight end, letters like F, H, or W for third, fourth, or fifth wideouts. Different systems have different preferences. In one system, the X receiver is typically on the left, Z on the right. In others, X is usually on the line of scrimmage, Z off. As offenses become more complex, even those in-system generalities get blurred.
Instead of explaining the difference between an X and a Z receiver, which is nearly impossible, let's go over the advantages and disadvantages of each position. A receiver on the line of scrimmage can release immediately into his route, and he is in good position to block his defender at the line. On the downside, he can be jammed easily. A receiver a yard or two in the backfield has extra space to beat a jam, which is why smaller receivers are often "flankers."
The wider a receiver's split, the more space he has in which to isolate and beat his defender. However, a receiver split wide of the field numbers has little room for running out-routes and other patterns that work the sidelines. Wide spacing also creates longer throws for the quarterback, which can be dangerous. Slot or flex receivers have space to work to the inside or out, can catch shorter, safer passes, and have a better chance of getting mismatched against a linebacker, safety, or nickelback in coverage. On the downside, they are working in tighter space; a slot receiver running a crossing route quickly moves from one defender's zone to another, making it hard for him to get open.
I have heard that old versions of the West Coast Offense funneled plays to the flanker, who was usually the Z receiver in their system. I have seen some WCO playbooks from the 1980s, and one thing that is striking is how often the Z-receiver went in motion. Factor in the motion and the fact that a flanker is hard to jam, and you have the perfect short-pass target from a three-step drop. That's an oversimplification, and I think the Z receiver got so much attention because his name was usually Dwight Clark or Jerry Rice.http://www.footballoutsiders.com/walkthrough/2009/walkthrough-camp-adventure