Playbooks

Four Verticals out of Shotgun Doubles Y Off sends both outside receivers straight up the numbers on vertical stems while the slot receiver runs a seam route up the hash, and the TE releases up the middle of the field as a fourth vertical threat. There is no run action or play-action element shown, this is a straight dropback pass with the RB staying in to help protect. The primary read progression works from the seams to the outside: check the middle of the field first on the TE and slot seam against Cover 2 or Cover 3, then work to the boundary verticals if the safeties widen or the corners bail late.
Pre-snap, check safety depth and width, if both safeties are shaded outside the numbers that is a Cover 2 shell and the seams will be the primary void. If there is a single safety sitting in the deep middle with corners playing off, that is Cover 3 and the vertical seams will get taken away while the outside verticals stretch the corners. Post-snap, watch for user-controlled safeties sprinting to double the seam route, that leaves the outside verticals in one-on-one coverage with the corners. Look for linebackers spying or dropping into the seam lanes, a nano blitz or zone blitz that drops an extra defender into the middle of the field will clog the seam reads and force a hot outlet check. Man coverage with no help over the top is the biggest vulnerability here, if you see man match or Cover 0 pre-snap the outside verticals should win against the sideline for an explosive shot play.
Pre-snap, identify whether you are facing two deep safeties or one, because that dictates which vertical route will be open. Against Cover 2, target the seam routes running up the hash before the safeties can get over the top, since the deep middle void between the two safeties is the natural throwing window. Against Cover 3, work the outside verticals on the corners who have to run with the receiver from the snap, since the single high safety cannot cover both sideline routes. Use hot routes to convert one of the outside verticals into a comeback or hitch if you see the corner playing deep off coverage, that turns this into a quick-strike answer versus soft zone. Pair this call with Slants or Angle Curls in the same set so that if the defense adjusts to take away the verticals, you can attack the shallow and intermediate zones on the next snap with similar formation recognition, keeping the defense guessing between shot plays and quick game.