Playbooks

Z-Close Curl aligns out of Singleback Doubles with the Z receiver closed into a tight bunch look next to the TE. At the snap the closed Z runs a deep crossing route all the way to the opposite sideline while the TE releases outside then breaks back inside on a curl. The backside X (isolated receiver) runs a shallow drift route across the field, and the primary read starts with the TE curl working the middle void before progressing to the deep crosser if a linebacker sits on the curl and to the drift route underneath if the defense drops deep. This is a zone beater designed to stress the flat and hook zones with three routes working different levels and horizontal spacing.
Presnap, check safety depth. Two deep safeties with linebackers sitting at five to seven yards signals Cover 4 or Cover 2, which opens up the TE curl read. Watch the flat defender and outside cornerback leverage. If the corner sinks to take away the deep crosser, the underneath drift route will be wide open behind him. Key the middle linebacker or nickel defender assigned to the hook zone. Aggressive blitz shows from that defender mean the curl route needs to sit down quickly for a rhythm throw. Man coverage with press corners and no safety help over the top is the primary shut down look, since the deep crosser gets picked up in trail technique and the curl has no natural window. Post snap, watch for a lurking defender sitting in the middle of the field on a Tampa 2 style drop, since that defender can undercut the TE curl if the quarterback holds the ball too long.
Call this on second or third and medium when you expect zone coverage like Cover 3 or Cover 4 that leaves natural voids in the intermediate hook areas.
Presnap, identify the middle linebacker depth. If he is sitting shallow to jump the curl, hot route the TE to a corner or seam to attack behind him.
Use the shallow drift route as a built in checkdown against pressure looks. If you see a nano blitz or overload look, get the ball out quick to that underlying crosser.
Pair this play with Flanker Drag or Y Shallow Cross from the same set so defenses cannot key on the deep crosser tendency without opening up shallow options.
Against man coverage, motion the closed Z before the snap to confirm man or zone leverage, since this concept is much less effective versus tight man coverage without a natural rub.