Playbooks

Mtn HB Slash lines up out of Singleback Ace Slot 12 personnel with a receiver put in motion pre-snap. Off the snap the HB runs a quick slash route to the flat while the outside receiver runs a vertical seam up the numbers and the backside X runs a deep vertical, creating a stretch between the HB in the shallow flat and two vertical clear-out routes. This is a play-action and RPO friendly quick-strike concept where the HB slash is the primary read against man coverage or a soft flat defender, with the seam and vertical serving as home run shots if the defense sells hard against the run or crashes down on the HB.
Pre-snap, check safety depth and count defenders in the box, a single high safety with a stacked box signals man coverage and an open lane for the HB slash. Watch the motion defender closely, if a linebacker or safety follows the motion man man to man you can key the HB slash as the primary answer before the snap even happens. Post-snap, key the flat defender or nickel defender's first two steps, if he sinks with the vertical route instead of stepping up on the HB slash you have an easy completion underneath. Beware Cover 3 or Cover 4 shells with a hard-sitting cornerback on the seam, this alignment invites a jump on the HB slash from a spying linebacker and shuts down the quick option. Look for a delayed blitz or nano blitz off the edge, since the HB is out in the route the backfield protection can be thin and a fast interior rush can disrupt the quarterback before the slash develops.
Use the pre-snap motion to identify man versus zone, if the defender follows the motion man across the formation you are getting man coverage and the HB slash becomes a near automatic answer against a linebacker in space.
Throw the HB slash quickly on early downs to keep the defense honest and set up the deep verticals later in a series once the defense starts jumping the flat route.
On third and long, look to the backside vertical or seam route immediately if the safety shell shows two high and there is no underneath robber, since the HB slash will likely be taken away by extra defenders.
Pair this play with HB Zone Alert Bubble and HB Stretch Alert Bubble in your call sheet to keep run and pass keys identical, forcing linebackers to hesitate before crashing on the HB route.
Use hot routes to convert the seam into a quick out if you see a corner sitting hard on the vertical stem, especially versus press man alignments.