Playbooks
Smash Z Under is a classic Cover 2 beater built out of the Shotgun Empty Trey Flex set, pairing a deep corner route to one side with a shallow under route from the Z receiver to attack the flat and hole zones. Since the formation is empty, there is no protection or run threat, this is a five man route concept designed to stress the underneath defenders and stretch the flat to hash vertically. The primary read starts with the corner route on the boundary to see if the deep half safety commits, then works down to the Z under route sitting in the void underneath the deep zone defenders, with the flat route as the checkdown against a hard squeeze.
Pre-snap identify whether the safeties are showing a two high shell, since Smash Z Under is built specifically to punish Cover 2 by putting the flat defender in a bind between the corner and under routes. Watch the cornerback depth at the snap, if he sinks with the corner route the under route will sit wide open in the void underneath, if he jumps the under route release the corner throw immediately. Key the flat defender or the underneath linebacker responsible for the hole zone, a hard squeeze on the under route opens up the checkdown flat route instead. Be wary of Cover 3 or Cover 4 shells with a user lurking underneath, since a sim blitz or a defender sitting in the throwing lane to the Z under route can bait a costly interception. If the defense shows man coverage with no safety help over the top, expect the corner route to be the higher value throw against a beaten cornerback rather than the shorter under route.
Check the safety alignment pre-snap, if you see two deep safeties split evenly this play is designed to punish that Cover 2 shell by putting the corner and under routes in conflict for the flat defender. Use motion or a quick glance to bait the cornerback into jumping the under route before releasing the corner route over the top. Hot route the backside route into a deep crosser if you are facing man coverage to give yourself a true man beater instead of relying on the smash combo. This play works best on second and medium to second and long where defenses tend to sit back in zone shells rather than blitz. Pair this call with Smash Y Sit or Stick N Nod in your play sequencing so the defense cannot key on the corner route tendency, then mix in Four Verticals later in the series to punish safeties who start cheating up on the under route.