Mickey Spags definitely has the article of the day as he examines the Cowboys defense in 2006. The basic question: How could they be so good for the first part of the season, yet absolutely collapse down the stretch? It’s a great question and plenty of people have plenty of theories. Which one you believe plays into your perceptions of the players, the coaches or the injuries.

Here’s the set-up for the different theories.

The theories are as many as they are diverse, ranging from that same old song of losing Greg Ellis for the season in Game 9 to Sean Payton knowing where all the bodies were buried to just plain running out of gas, which former ESPN analyst and Pro Football Hall of Fame inductee Michael Irvin the other day seconded the notion raised by Glenn, who said, "I don't know, just didn't have our legs under us. The last half of the season, it seemed like we were tired and our legs weren't quick. Happened the two years I was here. Like everyone was dead tired."

Let's take a look at some of the theories.

The Greg Ellis Injury:
While I think that this may have contributed to the Cowboys’ slide, I can’t say it’s the main factor. The reasoning goes that with Ellis out teams could slide their protection to DeMarcus Ware’s side, thereby negating the Cowboys pass rush. Its simplicity is its attractiveness. It allows us to easily assign blame and it allows us to believe that it is easily fixed by having a healthy Greg Ellis back or by inserting Anthony Spencer into the lineup.

But here’s my problem with this theory, if Ellis was doing such a good job in keeping the blocking evenly distributed between he and Ware, wouldn’t it follow that Ware’s sacks would be higher in the early part of the season and would decrease in the later part when offense were sliding their protection to him? But look at what the stats say using Ellis’ injury in the Arizona game as the demarcation line. Up through the Arizona game, Ware had 5 sacks in 9 games. After the Ellis injury, he had 6 ½ sacks in 8 games. Granted he had 3 of those sacks against the Lions and I don’t have numbers on QB pressures and the like, but the distribution of Ware’s numbers doesn’t seem to have been affected that much by pre and post-Ellis. So this theory doesn’t account for the defensive slide by the Cowboys for me.

The Vanilla Defense:
This idea maintains that the Cowboys defense under Parcells was so predictable that teams figured it out as the season wore on and learned ways to defeat it. I don’t buy this theory for one reason; Parcells has pretty much been running the same defense his whole career. Sure he had Belichick for a while who might’ve mixed things up a little whereas Zimmer wasn’t familiar enough with the 3-4 to make adjustments, but even in New England Belichick runs a very similar defense to Parcells. So if a team had wanted to study Parcells defense and figure out a way to defeat it they had years and years of film to watch in order to accomplish it. But as Mickey points out, for the first 10 games or so of the season the Cowboys defense was one of the best units in the league. This theory is shaky to me.

The Sean Payton Blueprint:
Under this supposition the main reason for the collapse of the defense was that Sean Payton showed the rest of the league what to do to score points on the Cowboys. In one sense, this is an extension of the Vanilla Defense theory because it says someone finally figured it out. But the reason this theory is a little different is because not only did Payton have intimate knowledge of the scheme, but he had intimate knowledge of the players themselves,  he knew their strengths and weaknesses and knew their tendencies better than any other opposing coach. He also knew the coaching staff’s thoughts and tendencies so he was in the best position to exploit it. Once he did, the rest of the league followed. Payton had knowledge that you just couldn’t pick up from watching film.

I give some credence to this theory. I think the teams that followed the Saints in playing us studied that game tape like it was the Gospel. It may have given them an advantage that previous teams didn’t have. So I can’t totally dismiss it.

The Tired Players Excuse:
This one is a little new to me but was brought up by a couple of players in Mickey’s article. I can’t get on board with this one. It implies that Bill Parcells was working his players so hard that by the end of the season they just didn’t have the legs to make the plays needed. Now, if the Cowboys defense was an aging unit that had a legion of games under their belt, then maybe, just maybe, there would be some truth to it. But the Cowboys defense is made up of a lot of young players. So to believe this theory you would have to believe that Parcells was putting them through extremely long practice sessions like no team before. It’s too much of a stretch for me.

The Players Failed:
To me, this is the most likely theory in combination with the Sean Payton Blueprint. I watched every game from last year at least twice, sometimes more than that, and I saw a lot of plays where guys were in position to make plays, but just didn’t do it. Especially towards the end of the season. We see it in sports every year; a team has a bad stretch, and they lose their swagger and it just starts to build upon itself until they just can’t get back to how they were playing previously. Granted, it’s a mysterious situation that is hard to define, and without a lot of logical backing. But it happens to sports teams every year. Once they lose that confidence they just can’t get it back and it builds on itself. One game is all it takes to set this in motion. So while I usually go with facts and stats to determine things like this, I just can’t ignore this theory.

A quote from Jason Ferguson nails it for me:

Then there is this from nose tackle Jason Ferguson, who readily points out Parcells' 3-4 style of defense "doesn't hide you - not a defense that will bail you out of stuff." He means, it's pretty basic. No tricks. Just mano a mano.

"Why didn't we do this? Why couldn't we help ourselves?" Ferguson said. "We stayed basic, stayed in the same thing and we didn't get it done as players."

So for me, I’m going with a combination of the Sean Payton Blueprint mixed with a healthy dose of The Players Failed. Call me a Parcells’ apologist or whatever, it’s just the way I see it. Of course, it’s not the only way to see it and I expect a lot of disagreement and ridicule from you guys. So let’s hear your pick of the theories, or better yet, if you have one of your own that I didn’t cover, write it up for the rest of us.