This is the only picture of Dean Pees available to us. He looks like a nice man.

Year in and year out, the Baltimore Ravens are in the playoff hunt and battling it out for the top of their division. They are one of the league’s most consistent teams. Just think about it for a second: how often do they sit at the bottom of the AFC North, like their division rival Cleveland Browns for example?

That just doesn’t happen in Baltimore, largely because of continuity. The franchise has had the same front office running the show for years, and veteran cornerstones (Ed Reed and Ray Lewis) on the field that are still playing for them. They draft well every year, they make low risk signings and trades, they are a tough team that’s battle tested, and everyone in the organization knows the team and their responsibilities inside and out. They also don’t fix what ain’t broke, especially when it comes to the defensive side of the ball. The Ravens’ last three defensive coordinators (Rex Ryan, Greg Mattison, and Chuck Pagano) were previously position coaches within their organization.

And now so is the next defensive mind in line: Dean Pees.

Pees was named the new defensive coordinator of the Ravens earlier this offseason after spending the 2010 and 2011 seasons as Baltimore’s linebackers coach. Pees comes from a rich coaching history, having worked with defensive gurus Nick Saban and Bill Belichick. Belichick gave Pees his first defensive coordinator job in the NFL in 2006, and that year New England was second in points allowed per game. From 2007 to 2009, the Patriots ranked fourth, eighth and fifth in points allowed per game, and they had one of the best defenses in the league.

But what did Pees’ defense do that made them so effective?

In those years, the Patriots were known for their ever-changing gameplans when they showed different looks each and every week, keeping offensive coordinators on their feet in study sessions. They also mixed in a lot of different looks prior to the snap of the ball that kept quarterbacks guessing in their pre-snap keys. Pees deployed over three dozen coverages a year under, which made the opposition put in extra study time in the week leading up to the game.

The abundance of coverages that the Patriots played were rooted in the two base coverages that they taught out of, Cover 3 and Cover 4.

Cover 3 is a 3-deep, 4-underneath zone coverage that’s sometimes used while defending against a run first offense, and the defense doesn’t want to cough up a big play deep. It’s also used to cover up any deficiencies that pass defenders might have because it enables them to get to a landmark and attack in the air.

Cover 3. (h/t

The three deep defensive backs divide their responsibilities into thirds and the cornerbacks play with an outside alignment on the receiver, attempting to force routes inside while also reading the quarterback. Underneath, four defenders divide their coverages into fourths and have their responsibilities split into two main assignments: Curl/Flat and Hook.

As I’ve written before, the Curl/Flat and Hook responsibilities are quite simple:

Hook – Hook defenders drop to the hashmarks of the field, hoping to fend off any pass receiving threats in the seam.

Curl/Flat - Curl/Flat defenders are responsible for defending outside the hashmarks as well as expanding outside to the flat if there are any threats posed in the area.

Further, there are variations of Cover 3 that defenses can deploy post-snap out of the usual alignments. These variations are known as Sky (safety drops down, 2 cornerbacks and 1 safety are deep), Cloud (corner drops down, 2 safeties and 1 cornerback are deep) and Buzz (a linebacker is a flat defender instead of a safety or a cornerback).

Much like Cover 3, Cover 4 (also known as Quarters) is flexible and can present different looks to the defense after the snap. In it’s traditional form, Cover 4 is a 4-across, 3-underneath coverage that has the cornerbacks playing the outside (#1) receiver while the safeties read run-first by keying the #2 (slot or tight end) as seen below.

Cover 4 or Quarters. (h/t for the image)

However, what makes coverage so popular is that all it takes is one check to roll into a different coverage. For example, the defense is initially line up in Cover 4, but then they see something as they are lined up that makes them want to get into Cover 3. With one signal, the defense can rotate a defender down or over from Cover 4 to Cover 3 after the snap. A seamless transition.

They can also get to Cover 2, for example, from Cover 4 with one signal or “check”. At the snap, the cornerbacks can just drop down into the flats and the safeties will widen, while the responsibilities of the underneath defenders stay the same. This is a bit more difficult to do when you’re working out of a 1-high shell, for example.

The coverage also enables a defense to disguise looks easily through tactics like pressing cornerbacks and bailing them at the snap, or going from a soft to hard corner quickly. This luxury is a big reason why Pees and Belichick used it as their base coverage, and they were able to confuse the likes of Peyton Manning in their matchups.

Pees is back to his defensive coordinator post that he last held with New England from 2006 to 2009. He is a quality defensive mind, having learned from Saban while at Michigan State and later Belichick, and now he’ll will bring a variety of looks to the already complex and fierce Baltimore Ravens defense. I expect a vast array of fronts, especially with Terrell Suggs out for an extended period.