In a mild surprise, the Dallas Cowboys fired defensive coordinator Rob Ryan after the 2012 season.

That led to one of the best quotes of the year from Ryan, who told ESPN the morning after his firing, "I'll be out of work for like five minutes."

As predicted, Ryan was hired by the New Orleans Saints four weeks later.

Now, after New Orleans crushed Dallas 49-17 on Sunday night, firing Ryan is looking like one of the worst personnel decisions of the offseason.

The Saints had the worst defense in NFL history last year. They gave up 6.5 yards per play, and 7,042 yards total in the regular season — crushing the previous record by almost 300 yards.

They've improved dramatically under Ryan.

The Saints have gone from 32nd in yards per game allowed in 2012 to 7th this year. They've gone from 31st in point per game allowed in 2012 to 5th this year. And they're doing so with six of the 11 starters that were on last year's historically bad unit.

This isn't the first time Ryan has overseen a dramatic improvement in defensive performance. The Cowboys were ranked 31st in the NFL in scoring defense in 2010 — the year before Ryan was hired as defensive coordinator. They improved to 16th in the league in his first year.

Ryan was fired after his unit slipped to 19th scoring defense and 24th in total defense in 2012. But there are some valid excuses for that regression.

Cowboys starters missed 38 combined games due to injury last year, according to Jonathan Bales of the Dallas Morning-News. In addition, Dallas' defense was among the 10 best units in the league through the first 10 weeks when everyone was healthy.

Said Ryan:

"I inherited a team that was 31st in the league in defense and made them better. I (expletive) made them a hell of a lot better. I'll be out of work for like five minutes.

"I think I did a good job and I think our staff did a good job on defense trying to compete with what we had at the end of the year. But the best job we did was when we were able to coach our starters."

Now Dallas' defense is significantly worse than when Ryan first got there. They're dead last in yards allowed, and are on pace to challenge that Saints record from last year. They're 31st in yards per play, 32nd in first downs allowed, 25th in third-down percentage, and 23rd in scoring defense.

The Cowboys are 5-5 and haven't been able to break away from the pack in the NFC East, despite the fact that Tony Romo is having his best year ever.

Last night owner Jerry Jones seemed to acknowledge that firing Ryan may have been a mistake. He told ESPN:

"We thought it was best for us to go in the direction that we are, and it doesn't look good right now. Hopefully we can make it look good, but I have all the feelings that you have when you want to look back at a decision, and I realize when some of them work you have to have a few things go along with it.

For all the money the Cowboys have spent in free agency and all the high draft picks they've traded up to get, firing Ryan is looking like the most costly move the franchise made this year.