Thanks for sharing!
Here is another article from Bleach Report that discusses Cover 3 Concepts.
One thing to also keep in mind, is the kind of personnel required takes to to implement this kind of scheme. Cover-3 puts three defenders in deep zones over the top of the defense, with the middle of the field “closed” by a free safety—usually Earl Thomas, a player with unique range from that spot. That free safety effectively takes away any post pattern, and the range of Thomas—coupled with the deep zones on the edge—ward off any other deep pattern. When the defenses play man coverage, it forces offenses to challenge some elite coverage defenders, like Richard Sherman, a fast, hard-hitting player who will can punish you if you attack him often enough.
Having a premier free safety and an elite cornerback is the only way that a like Seattle can safely defend deep passing zones with three players and use eight-man fronts (giving them both a one-for-one match of the eight run gaps and four underneath pass defenders to patrol the intermediate passing zones.) However, we’ve also seen the Jaguars implement Seattle’s famous press cover-3 scheme, running a 3-shell more than any other team in the NFL, without being able to replicate Seattle’s success.
Quinn is basically trying to reproduce the Seahwaks defense in Atlanta and when Atlanta hired him from Seattle, Dimitroff knew they needed to add more talent. That's why they picked two linebackers and a safety in the first four rounds of the 2016 draft (Deion Jones, De’Vondre Campbell, and Keanu Neal) and unearthed Brian Poole (a rookie free-agent corner).
Atlanta’s defense has excelled in some areas and really struggled in others. For the most part, the Falcons have relied heavily on their offense to keep them in games all season, and their defense has been more accustomed to protecting leads. But they still have good athletes on defense. The defensive line and linebacker units are getting better and have shown tremendous promise at times throughout the season. Jones and Neal fly fast to the ball and have become two of the best open-field tacklers on the team.
They are playing faster and smarter in all phases, which has stabilized many of the personnel packages Quinn spent the first half of the season tinkering with. They're also starting to shift to more man coverage as the season has progressed (essentially making man-to-man their second foundation).
But most people agree that their defense is young, athletic, and inconsistent. The median age of its 11 most-used defenders is 24, and seven of those guys are in their first or second seasons. This makes them prone to miscues and youthful mistakes at times.
In theory, Cover-3 might seem like a much easier defense to play than man coverage, because you’re watching the quarterback most of the time, but there is more to it than that. Corners need to be able to understand route combinations, alignment, and tendencies, and have to learn when zones change from how they’re drawn up on the chalkboard. Those complex assignments can also be Atlanta's undoing if an offense is good enough to identify them, as well as the bind they can place defenders in. And that’s usually when Brady goes to work at the line of scrimmage, sniffing out the coverage before the snap and audibling to a play that will work. Against zone, expect a lot of throws over the middle, as we saw against Pittsburgh. Against man, we’ll see crossers, slants, and pick plays.
Given what we've seen in the past, you could also argue that the Patriots’ offense is almost uniquely suited to succeed against the Cover-3 defense. Brady faced a similar (more talented) defense in the Super Bowl two years ago, and finished with 328 passing yards, four touchdowns, and completed 73.5 percent of his passes. Brady also faced a similar defense when the Patriots played the Jaguars in Week 3 of 2015, throwing for 358 yards and two touchdowns in a 51-17 win. The Patriots had nine offensive possessions that game, and scored a touchdown or field goal on all nine.
