The way I interpret it is that when Brady calls out 53 is the Mike it sets a certain protection and blocking scheme. The defense has to have some idea how the offensive line is going to adapt based on this due to film study coupled with the broadcast audio. So what if the defense is predicated upon Brady's calls? If Brady calls 53 is the Mike the defense switches from one scheme but if 55 is called another. Later in the game I heard Brady say 53 and 55 are the Mike and another time I thought I heard him say 53 is the Mike and 55 is the Will. I couldn't remember Brady doing this in the past and I had wondered during the game if they picked up on Buffalo shifting upon their line calls and this was how they dealt with it on the fly.
First off if true credit Rex for coming up with it. I had actually wondered if teams did this for a long time and if not why the hell hadn't somebody thought of it. Second if the Pats picked up on it that fast it probably did mean somebody has tried this in the past but if not that just lends to the legend of TB/BB/JM for so quickly coming up with a countermeasure. Likely the Patriots themselves have employed similar especially against very predictive foes.