New England Patriots quarterback Tom Brady isn't the most athletically gifted quarterback in the league- some might even say he's relatively unathletic compared to his competition. A lot of players are stronger and most players are faster, but it's the nuances of the game that allows Brady to surpass the players who get by on their talent. No one maneuvers the pocket better to avoid the pass rush, and absolutely no one is better at diagnosing the opposing defense prior to the snap.
There are myriad factors to evaluate prior to snapping the ball; this is an element that hasn't been quantified (and it's unlikely it ever will with any success), and it's hard for sites to incorporate into their grading reviews. Quarterbacks have to look at defensive alignments at all levels of the field- where are the linebackers? what are the depths of the safeties? are the cornerbacks showing man or zone coverage? is there a potential blitz? is the defensive line showing anything that an audible could counter?- and they have to do it all prior to the snap.
Players improve their diagnosing ability by watching and watching and watching film, and Brady is one of the biggest film junkies in the league. Another tape nut is NFL Film's Greg Cosell, who watches more tape than possibly anyone. Cosell sat with Frank Schwab of Yahoo! Sports to shed some light on what a quarterback might look for prior to the snap, using Aaron Rodgers and the Packers against the Vikings.
Here's just an excerpt from the article to show the depth offered:
There was no blitz indicator from the Vikings on this play. If corners are playing tight man coverage, that could be a blitz indicator, but they weren't here. The linebackers were stacked behind the line, and that was an indication they would not blitz. It would be different if a linebacker was up on the line of scrimmage or creeping up to it. The safeties showed two-deep shell, and that's not a blitz indicator. Anything can change at the snap because teams will try to confuse the offense, but the Vikings' alignment indicated this was a zone coverage with no blitz. It's hard to blitz out of a two-deep shell, because you have two safeties deep and if you take another defender out of the front seven to blitz there are a lot of voids in the defense.
We will be doing more film breakdowns over the next year, so having a greater understanding of the process is a crucial aspect of learning the game. Cosell learned how to watch tape from his relationships with former players and coaches and he will be providing an extremely transparent opening into how the professionals do their job.
This is part one of a season-long series from Schwab and Cosell, so we'll provide updates when they come across.