Playbooks

Drag Verticals from Shotgun Trey Open sends three verts up the field from the trips side while the backside receiver and the middle route work underneath. On the diagram, the two outside trips receivers push vertical up the sideline and one bends into a deep in cut, the inside slot vert climbs up the seam and breaks back across the field on a deep crosser, and the backside X runs a shallow drag underneath everything from the opposite side of the formation. This is a route concept built to attack both zone and man coverage by stretching the field vertically with verts while the drag and the deep crosser give you answers underneath and across the middle. The primary read starts with the seam vert working into the deep cross, then works down to the drag as the checkdown if the deep routes are covered.
Identify two deep safeties pre-snap as your first Cover 2 indicator, this concept is built to exploit the seams and hole in that shell with the vertical routes and the crosser. Watch the middle linebacker depth at the snap, if he sits shallow and doesn't widen with the drag you have an easy underneath completion. Key the slot cornerback or nickel defender on the seam vert, if he opens his hips late or gets picked off by traffic from the crossing route the deep completion is there. Beware Cover 3 shells with a rat linebacker sitting in the middle of the field, that defender is designed to jump the deep crosser and the drag so you may need to layer the ball or check down late. User controlled defenders lurking underneath in the flats can bait a drag throw, so scan the flat before committing since a jumped route there leads to a live ball for the defense.
Use this on early downs or second and medium when you have time to let the verticals develop and work through the full progression.
Check the safety alignment pre-snap, two deep safeties tips Cover 2 and tells you to look for the deep crosser settling in the void between the safeties.
Against single high looks, hot route the drag into a deeper option if the underneath defender is sitting on it, since Cover 3 defenders will often rob that shallow crossing route.
Pair this call with Curls X Go or Four Verticals earlier in a drive so the defense starts respecting the vertical stems, then come back to Drag Verticals to hit the crosser once linebackers start cheating up on shorter routes.
If you see man coverage indicators like tight press alignment on the trips receivers, trust the deep in cut and the crosser to win separation against man defenders trailing from depth.