Slot corner D.J. Moore recognized the Bills were likely to run a smash concept with the two receivers to that side, sending the outside receiver on a slant and the inside guy on a corner route. He desperately signaled to RCB Josh Norman to switch if the receivers cross. Instead of each tracking their man on their respective patterns, if the receivers cross the corners would switch assignments and track the incoming man, putting them ahead of the play and not trailing it — something vital in these tight quarters down by the end zone.
So, to illustrate why Norman hasn't been starting despite his preseason showing, it's apparent that he is still struggling to understand situational coverages. While some here will blame coaching for him failing to recognize the obvious, notice that DJ Moore, who is a newcomer to the Panthers defense, knew exactly what was going on.