Playbooks

Z Spot is a five-man empty concept out of Shotgun Empty Bunch Y Flex that attacks the underneath zones with a classic Spot combo on the strong side. The bunch releases a corner route, a quick spot (settle) route, and a flat/angle route that all stack levels underneath the deep corner, while the backside runs a deep comeback and a vertical clear-out to hold the single defender. There is no run action and no protection to read since it is empty, so this is a pure dropback pass designed as a Cover 3 beater, with the QB progression starting on the spot/flat combo underneath before working to the backside comeback if the zone flows away.
Pre-snap, check safety depth and corner alignment to identify Cover 3 versus Cover 4, since this concept is built to exploit the seam left by a Cover 3 curl-flat defender. Post-snap, watch the flat defender's drop, if he sinks too deep the QB will take the spot route sitting underneath him for an easy completion. Look for a user-controlled defender lurking in the middle zone, since the spot route settles in a shallow window that smart users can jump if they anticipate the throw. Against man coverage, watch the backside comeback route defender, if he opens his hips too early on the vertical stem he will get beat on the break. Blitz packages that bring five or more rushers against empty can disrupt the timing quickly, so a fast interior push forces the QB off his first read before the spot route settles.
Use pre-snap motion or a quick glance to identify if the corner is playing off or bailing into a zone drop before the snap.
This play is best called on third and short to third and medium since the spot route settles quickly and gives the QB a rhythm throw underneath.
If the defense shows Cover 3 with a hard flat defender, hot route the flat man to a flat sit or speed out to widen the throwing lane.
Pair Z Spot with Dagger or Speed Dig Out from the same set so the defense has to respect both underneath spot concepts and deep in cuts, forcing zone defenders to hesitate.
Against man coverage, key the backside comeback route since it creates natural separation off the break against a trailing corner.