Pats D opened with man to man over the top, with Arrington on Marshall, and LB in coverage. As posters here have discussed, Wilfork was put in as LDE and the defense was aligned to draw a strongside run that they could push out. On that 3rd and 3 long completion 13:21 1st Q. The D was in cover 1 underneath (Mayo) with an athletic linemen lineup (Cunningham, Pryor, and Wright). Both OLB dropped back to cover the curl/flat and backfield was still in man to man, with the exception of Sanders who was in a strongside cover 2 (for the run). At the snap weakside was cover 0, but Meriweather dropped back to become cover 2. When you first see the play breakdown, it's easy to either blame Guyton (who fell down after running into Hartline) or Chung, because as the SS it's easy to presume it's his responsibility to fall back, but the culprit here is Mayo because he is in zone coverage and should have picked up Fasano on the seam. Instead he doubles up on Hartline, unaware that Chung is already shadowing him. However, you could make the argument that it was easier for Chung to hand off Hartline to Mayo and just drop back with Fasano, simply on recognition. This is something that can only be worked out through experience, in terms of feeling the play develop and to know when to freelance and when to follow the assignment. In the first still, you see Mayo in coverage, and in the second you see him pick up and move with Hartline while Chung is doing the same behind him (shadowing).