The following is a breakdown of the Seam drop that is explained in Dick Lebeau's playbook from the 2002 Cincinnati Bengals. To begin Lebeau defines Seam on page 20 of the .pdf in the Secondary Coverage Terms section of the playbook as "Outside in technique on #2. Must carry vertically or to the flat. (Fire Zone Term)". Later Lebeau gives 3 coaching points for the seam drop in the Fire Zone Coverage Rules section of the playbook on page 144 of the .pdf.
- COLLISION FROM OUTSIDE - IN
- CARRY ANY SEAM ROUTE UPFIELD UNTIL RECEIVER ATTEMPTS TO CROSS YOUR FACE FROM INSIDE OUT (Exception: Slash Release)
- ALWAYS COME OFF ON #3 RECEIVER CROSSING YOUR FACE TO FLAT
CORNERS - DEEP 1/3 BUT NO 2 TO 1 READ
ENABLES CORNERS TO GET TIGHTER ON #1 RECEIVER (Alert Stack or Slash Release)
SEAM PLAYERS WILL CARRY SEAMS TO FREE SAFETY
NO CHINA CALLS IN FIRE ZONES
Based on the rules and diagrams in the playbook here is my analysis of the seam technique.
If #2 releases immediately inside, the Seam(SM) player will carry and deliver the crosser to the next color (3RH or opposite SM player). The Seam player must be aware of the level of the next threat represented in the diagram above as the vertical dashed line. The SM cannot cross that level to avoid being out leveraged by #3. If #3 is staying in to block, the next threat to the SM is coming on a crossing route from the other side of the formation.The same concept is utilized for the Slash release.
A slash release occurs when #1 and #2 are in a close proximity split alignment and the #1 receiver releases immediately underneath. The SM player will treat the fast crosser (#1) just like #2 on a fast crosser. The SM will carry and deliver with understanding of the level of #3. The corner will squeeze to the #2 receiver's vertical route on the slash release. The corner and seam player are reminded in multiple places in the playbook to be alert for the slash release based on the formation or crack motion by the #1 receiver.
The Slash/Flat combo is handled by the SM player carrying the #1 receiver inside before reacting to #3 to the flat. The #1 receiver on the quick crosser will be taken by the 3RH dropper who is looking for something coming back in when #3 goes out.
If #2 is vertical the SM will carry the vertical until a receiver attempts to cross his face from the inside out. The #2 receiver could attempt to cross the SM players face on an out cut in which case the SM will be in good body position to defend that out cut. If the #3 receiver is going to the flat the SM must come off #2's vertical and cover the #3 receiver to the flat. If the #3 is aligned in a trips formation the SM player needs to be alert to a higher probability of being out leveraged by #3 and be prepared to come off #2 vertical. It is unlikely that a crosser from the other side of the formation will be able to get across quickly enough to out leverage the SM player but it is possible and the SM player would need to come off on the crosser.
If #2 is out the SM player stays over the top of the route and runs through the window of #1's route before driving on #2 to the flat. The SM player has #2 on the wheel because the corner is playing aggressively on #1.
The SM player is responsible to drive on any 3 step or hot throw to the #2 receiver.