by Cian Fahey

In 2012, the New Orleans Saints had the worst defense in the NFL by DVOA. That defense was severely limited by a secondary that lacked athleticism, versatility and technique.

Since that season finished, the Saints have set about revamping that section of their roster. Cornerback Keenan Lewis was brought in as a free agent with a five-year deal, after just one year as a starter in Pittsburgh. He was joined by safety Kenny Vaccaro, taken with the 15th overall pick in the 2013 draft.

Lewis' physicality on the outside and Vaccaro's exceptional coverage ability, both in the box and as a deep safety, immediately upgraded the team's defense as a whole. Each player played a significant role in helping the defense rank 10th in DVOA for the 2013 season, including an impressive sixth against the pass.

With Drew Brees' championship window closing, the Saints made further moves to improve their defense before this season, adding Jairus Byrd, Champ Bailey and rookie Stanley Jean-Baptiste. Bailey never made the final roster and Jean-Baptiste is a raw rookie, but Byrd was always going to be the key addition.

Byrd was signed to be the perfect complement to Vaccaro. Both are versatile players, but Byrd primarily excels as a deep safety while Vaccaro does his best work when he lines up closer to the line of scrimmage. With Rob Ryan as the team's defensive coordinator, this secondary should have allowed the defense as a whole to flourish.

In Week 1, that didn't happen.

The Saints were facing the Atlanta Falcons, a team that has significant weaknesses on their offensive line, but exceptional talent at the wide receiver positions outside. The Falcons' running game ranked 21st in DVOA last year, and they made no major upgrades at the relevant positions entering this season. With that in mind, it's no surprise that the Saints decided to play Cover-2 on a regular basis in this game.

The above image shows how the Saints lined up on the first three snaps of the game. This wasn't something they got away from as the four quarters developed. By keeping both safeties deep, the Saints were theoretically trusting their front seven to contain the Falcons' running game and allowing their cornerbacks to be more aggressive underneath against the Falcons' receiving options. What happened in practice was a lot different from what was supposed to happen in theory.

Most worryingly for the Saints, their failings appeared to be a combination of poor play on the field and poor game-planning from the sideline.

A constant issue for the Saints was the space that appeared between their safeties and their underneath coverage. Not only were the Saints safeties regularly lining up in deep positions, but they were also dropping further downfield at the snap. Jairus Byrd in particular was often dropping into zones that completely took him away from positions where he could impact the game. On the above play, Byrd can't close on the ball quickly enough to cover for a blown assignment in front of him. Matt Ryan has plenty of time to find a wide-open Roddy White on the deep out route.

White was a constant thorn in the Saints' side. The negative side of keeping both safeties deep was that it gave White more space to work in underneath, and he was able to find matchup advantages.

On this play, not only are both safeties aligned deep down the field, but so are both cornerbacks to the bottom of the screen. White is lined up as the inside slot receiver to the bottom of the screen. The play call and alignment from the Saints puts him in a man coverage situation against linebacker Curtis Lofton. Lofton is a run stopper who doesn't have the agility to stick with White. He should only be asked to cover White when he is giving or receiving help from a teammate to close off space.

The result of the defensive alignment and play call pits Lofton against White in space. White runs a simple out route and Ryan immediately finds him for a good gain. Giving up this play underneath would be perfect against this defense if the coaching staff was trying to force a three-and-out in a third-and-long situation, but this play occurred on first-and-10.

White caught five passes in this game. Not a single one of those catches came against Vaccaro, Byrd or Keenan Lewis in man coverage. Instead, he took advantage of the space afforded to him against less talented defensive backs and linebackers.

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On this play, the Saints line Byrd up 25 yards off the line of scrimmage to the right side of the defense. Byrd moves towards the far sideline at the snap, leaving the Saints' cornerbacks to the bottom of the screen in one-on-one situations with no help. That means that White is running a curl route against Corey White, a physically inferior player who is predictably beaten at the catch point when he has to account for the deep threat.

Significantly, even if Corey White covers Roddy White, the secondary still blew an assignment on the other side of the field to give Matt Ryan a wide-open receiver running down the middle. Byrd should be in the middle of the field to both cover this blown assignment and allow Corey White to be more aggressive, but instead he is hugging the far sideline and completely out of the play.

The Falcons missed the big play on this occasion, but they found many, many more.

Devin Hester was the biggest benefactor of the Saints' inability to run an effective defense. On this play, the Saints were again in a Cover-2 alignment. This time Byrd was to the top of the screen and Rafael Bush was aligned to the bottom. Roddy White runs a post route from the slot to Bush's side of the field. White is well covered by the defender underneath, but he draws the attention of Bush, who completely abandons his deep half of the field and runs with White to leave huge space into which Matt Ryan could throw the ball.

Because the outside cornerback was expecting to have safety help over the top, he was always going to lose a race down the sideline to Hester in this situation. The cornerback was expecting to play the underneath routes aggressively and shadow his assignment to his safety if he went down the field. He did that, but the safety wasn't there to prevent the reception or force Ryan to look elsewhere.

Bush is going to be a fixture in the Saints' secondary this season when Vaccaro moves down to cover tight ends or receivers in the box. At least, that was a logical expectation before this game.

In this game, the Saints did use Bush deep and drop Vaccaro into the box, but in key moments Vaccaro wasn't covering receivers or tight ends. He was covering running backs. On the Falcons' field-goal drive at the very end of the second quarter, Vaccaro dropped into the box alongside linebacker Ramon Humber. Vaccaro lined up to the left side of the defense, while Humber stayed on the right.

As the play developed, it became clear that Vaccaro was being used to cover Jacquizz Rodgers in man coverage, while Humber was dropping deep over the middle of the field. In this situation, Rodgers isn't as big of a threat to the defense as Hester, who is lined up in the slot to Humber's side of the field. In any situation, Vaccaro is better equipped to cover Hester than Humber is.

Eventually, Humber ends up in a position to attempt to cover Hester but he doesn't have the speed to break on the ball before him over the middle of the field.

Immediately after Hester's first play against Humber, Ryan finds Roddy White down the seam working against Rafael Bush. Again, on this play Vaccaro is covering the running back in the flat. Vaccaro and Byrd are supposed to be the strength of this team's pass defense, but at a crucial point Vaccaro is being given an assignment of very little value.

There is no guarantee that he would have prevented either of these plays and hindsight makes it an easy decision, but even logically before the plays began it made little sense to use the available personnel in this way.

If the Saints are expecting Rob Ryan and their revamped secondary to help the franchise find its way to the Super Bowl, a lot will have to change from this performance.