Playbooks

HB Gut is a downhill run play out of Weak I with 22 personnel that sends the halfback through the gut of the interior line behind lead blocking from the fullback. The diagram shows the FB kicking through the hole first with the HB following on a tight, direct path between the tackles, meaning there is no route tree to read since this is a designed run concept rather than a man or zone beater. The primary read is the frontside guard and center double team, with the HB keying the fullback's block to decide whether to press the A gap or bounce off the FB's lead block into the B gap.
Pre-snap, count the box defenders and check linebacker depth, if the Mike and Sam are stacked tight to the line they are reading run fast and will fill the gut lanes immediately. Watch for a stacked front or a 4-3 under alignment with the nose shaded to the play side A gap, this can clog the primary running lane before the fullback gets a clean kick block. Man beater and zone beater concepts do not apply here since this is a pure run, so defenders should key the fullback's first step rather than backpedal into coverage drops. Blitz packages with a linebacker or safety crashing off the edge unblocked can blow this play up quickly, spy or add an extra run fit defender if you suspect Gut based on personnel and formation tendencies. If the offense has shown HB Gut multiple times from Weak I, sit on the fullback's block angle and user the strong side linebacker downhill into the mesh point before the HB can decide his gap.
Run this out of Weak I when you have a numbers advantage in the box, since Gut relies on winning the point of attack physically rather than scheming defenders out of position.
Check the defensive front pre-snap, if you see six or more in the box on early downs consider audibling to a play-action shot off this same look later in the series to punish overaggressive run fits.
Use manual control on the fullback if you are comfortable user-blocking to seal off a crashing linebacker or slanting defensive tackle at the mesh point.
Pair HB Gut with PA Waggle and TE Flat from the same formation and personnel group so the defense cannot sit on run keys, since all three plays share the same initial backfield action.
This is a strong early down, short yardage, or goal line call since it is designed to move the pile forward, avoid calling it on third and long where you need explosive yardage.