i would hardly call knowledge of the playbook "my opinion"
(complete with diagrams and actual playbook from 10 yrs ago)
The "Seam" drop I am referring to is technique of the player who is dropping over the #2 receiver in a 3 under 3 deep fire zone coverage. I have also heard this drop called Scif, Bronco, and Deuce. Regardless of the name, the execution of this technique has a direct correlation to the effectiveness of a team's fire zone pressure package.
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
just as i am entitled to MY opinion, everyone else here is entitled to an educated opinion as well.
in just 3 games we have already seen the new "penny" defense, FACT
"big snackle" [as i call it] (NT stays in for big nickle packages), FACT
and i am certain there were sub-packages of big nickle utilizing sean spence instead of 3 safeties.
but yeah, lebeau is too lazy and set in his ways to adapt.