How Saints' Rob Ryan went from honeymoon stage to divorce

Saints fire DC Rob Ryan (2:24)

ESPN Saints reporter Mike Triplett explains why the team decided to part ways with defensive coordinator Rob Ryan and what the future holds for Ryan. (2:24)

METAIRIE, La. -- Rob Ryan had to go.

And that's a shame, because the dynamic defensive coordinator was such a great fit for the city of New Orleans when they fell in love with each other back in 2013, when Ryan lifted the New Orleans Saints' defense from 32nd in the NFL to fourth.

Ryan was buying drinks for the house in a local bar after games, serving as the grand marshal in a Mardi Gras parade, marching through the Irish Channel, dancing at Greek Fest.

Man, does that feel like a long time ago now.

It's a shame, too, because players seemed to love playing for Ryan -- especially in 2013 when they were winning. His energy, passion, creative motivational tactics, diverse schemes and self-deprecating wit all made him kinda lovable.

Even Sean Payton seemed to be rooting for Ryan because he admired his passion and tireless work ethic. That's why Payton kept Ryan around in January when it felt like Ryan might be fired after an ugly 2014 campaign.

When Payton announced Ryan's removal on his WWL Radio show on Monday night, he said, "I'm disappointed for Rob it didn't work out. … He's a fantastic staff guy, respected greatly, not only in the locker room but by his peers."

But Ryan had to go because the Saints defense has become spectacularly awful.

Like all-time-worst-in-the-NFL awful.

The Saints (4-6) are currently on pace to shatter the NFL record for opponents' quarterback rating (116.5). They're on pace to allow the second-most yards in NFL history (424.7 yards per game, behind only the 2012 Saints under another fired coordinator, Steve Spagnuolo). And they just set a dubious mark by becoming the first defense ever to allow four touchdown passes in three straight games without an interception.

Kirk Cousins just posted a perfect passer rating for the Washington Redskins with four touchdown passes in a 47-14 rout of the Saints on Sunday.

Ryan had to go.

"We just had to look closely at some point to at least give this an option, because the direction we were heading wasn't good," Payton said.

No one could argue with that.

In the end, what killed Ryan was the same thing that plagued him in previous stops such as Dallas and Cleveland: His defense was too undisciplined.

Nothing drove Payton nuts more than guys getting lined up wrongly. Whenever the defense had 10 or 12 men on the field -- which happened far too often -- all the binoculars in the press box and the TV cameras would turn to watch the inevitable Payton shouting tirade directed at Ryan. Payton mentioned those substitution errors while explaining Ryan's dismissal on Monday.

Assignment and alignment errors after the ball was snapped became an epidemic in 2014, too. That hasn't been the case as much this season -- largely because Payton forced Ryan to simplify his scheme and cut down on all the substitutions and checks at the line of scrimmage.

Payton also brought in senior defensive assistant Dennis Allen to help serve as a fundamental teacher for the secondary. Everyone immediately labeled Allen as Ryan's replacement-in-waiting. Sure enough, Allen is taking over now.

In retrospect, perhaps Payton should have just made this move back in January since it felt so inevitable. And maybe it wasn't fair to Ryan to force him to run a defense that wasn't his own creation. Ryan made a lot of subtle comments throughout the season about how it was Payton's "vision" or Payton's "blueprint" and Ryan was in charge of implementing it.

Or maybe none of that matters since the defense has too many injuries and not enough proven talent. The Saints' linebacking corps and secondary have especially been depleted by injuries throughout the year.

The Saints switched to more of a press-man coverage scheme with a single-high safety this past offseason, but that hasn't worked since the big, physical cornerback they signed in free agency, Brandon Browner, is leading the NFL in penalties. The other starting corner, impressive Canadian Football League transplant Delvin Breaux, has also battled penalty issues.

It's hard to imagine Allen will provide a drastic upgrade over the final six games of the season, even if linebackers Dannell Ellerbe and Hau'oli Kikaha come back from lingering injuries.

Maybe Allen will help cut down on the alignment errors and even the penalties. Maybe the move will spark a renewed sense of urgency. Maybe not.

Regardless, Ryan had to go because the Saints just lost 47-14 and gave up 394 yards in the first half against a mediocre Redskins offense.

Ryan had to go because this defense can’t get any worse right now.