Its the game of the week: the Dallas Cowboys versus the Pittsburgh Steelers in a matchup of classic rivals in poor conditions. There are many storylines surrounding the game between field conditions, DeMarcus Ware's and Marion Barber's status, the weather.....field conditions. Rafael has a excellent piece below detailing the under appreciated matchup of the Cowboys' defense and the Steeler's very vanilla offense. Yet the main storyline heading into the game has centered around whether the Cowboys' offense can solve this all-time great Steelers defense, led by James Harrison and Troy Polamalu.

But just how good is this vaunted Steelers defense? Are their incredible numbers a result of great play or just not playing good offenses? How do they rank historically?

Follow the jump to find out.

When I set out on this endeavor of analysing the Pittsburgh Steelers' defense, I was unsure of what I would find. I am always skeptical when the media really gets behind a certain team's defense or offense, especially when I hear the same stat over and over and over again. Is there only one stat that proves just how great an offense or defense can be? If it's so great, why aren't their a whole bunch of numbers to back up everyone's point? We all know what they say about stats and numbers: lies, dang lies and statistics. Numbers can be used in any way to prove a point, skewed in the direction you want them to go. That's why when I present stats here in this forum I do my best to show the whole story, and then decide what those numbers have helped prove.

In this case, the media has not stopped bringing up the fact that the Steelers defense has not allowed over 300 total yards yet this season. At first glance, this is an amazing stat and leaves you wondering just how in the heck can Dallas crack such a tough shell. I see those numbers and it makes me think about what factors have led to such an incredible stat. Does the defense cause a whole bunch of turnovers that cuts drives short? Does the offense do a great job of controlling the clock to keep the defense off the field, maximizing the performance when they are? Does the defense focus on shutting down one aspect of an offense and then dare to be beat with the other? All of these questions I wanted answers to when I started my statistical journey into the vortex that is the Pittsburgh Steelers defense.

The Steelers defense wins games, not the offense. Right?

The Pittsburgh offense ranks 24th in the league. They aren't explosive and they give up way too many sacks (although they have become better at protecting Roethlisberger lately). Yet despite having a very simple offense the team is 9-3 and is poised to win the AFC North.

So that leads us to believe that the defense has a high rate of turnovers, scores defensive points and helps the offense by putting additional points on the board. Right?

A couple of things surprised me about these numbers. First of all was the low defensive points. Usually when a team has a top ranked, highly touted defense you a high number of purely defensive touchdowns, interceptions and fumbles returned for a touchdown. For the season the Steelers have a safety and a fumble return and that is it. Now, that is certainly not bad but over half the teams in the league have returned an interception for a touchdown. Very interesting for the league's best pass defense.

The second thing that stood out to me was points the offense scored that came directly from turnovers. By listening to the media, and fans alike, you would think that the Pittsburgh defense is a turnover machine. A lot of that hype has stemmed recently from all of the turnovers forced against New England. Yet the Steelers average 1.66 turnovers forced per game (the Cowboys average 1.33), putting them somewhere in the middle of the pack league wide. The bad news for the Cowboys is that the Steelers offense makes use of every single turnover; only once this season have the Steelers failed to score following an interception or a fumble. In games they have won, the Steelers average nearly seven points off turnovers a game. Conversely, in games they lost they averaged just two.

So the Steelers' defense doesn't score often and doesn't force a ton of turnovers. So what is that makes them so great?

The Steelers pass defense is the best in the league.

Much has been said about how quarterbacks with great numbers and good ratings have gone up against Pittsburgh and come out of it with their stats hurting. The media is always quick to point out how Philip Rivers and Jason Campbell had league leading numbers before their games against Pittsburgh, yet had horrendous games. What they fail to mention is what happens when accurate, poised and experienced quarterbacks face the defense. What happens? They lose.

Peyton Manning, Donovan McNabb and Eli Manning all won against the Steelers and they did it by being as efficient as possible. While the Steelers do get a bunch of turnovers, where they are most succesful at hurting quarterbacks is through pressure in the pocket. We all know about Harrison and Woodley and that Pittsburgh has the most sacks in the league. The key for teams that have won has obviously been the fact that they were able to protect their QB. Even though these quarterbacks were more succesful than others, they still were unable to put up big numbers. The key was not allowing drive ending sacks or turnovers, which as we stated above puts their offense in prime position to advantage and score.

Scoring: The Steelers defense does not allow points, but how good are the teams theyve faced?

Quick explanation of this table: the offensive and defensive scoring averages are the average score teams have scored and allowed when NOT facing Pittsburgh. This gives a good luck at how teams perform relative to what happens in the game against the Steelers.

There's no doubting that the defense's stength is not allowing teams to score, at all. Only twice this season has a team scored more points against the Steelers than they averaged against the rest of their schedule. More importantly however, is that while the Steelers offense may not be flashy, over half the time they score more points than opponents allow on average against other teams

The Steelers are 3-3 when facing teams with winning records. Two wins have come against bottom dwelling Cincinatti. More importantly though, the Steelers defense has faced just three offenses ranked in the top ten. They lost to two of them. This isn't to say that the Steelers should be sorry for playing in a division with two bad teams; you can only play who the NFL puts on your schedule. But the point remains that when facing successful teams with high ranked offenses and winning records, it isn't a given that the Steelers will win.

How do they rank historically?

This year the Steelers' defense is allowing 238.0 yards per game, with average of 3.9 yards per play.  Most impressive is the fact they are allowing just 3.1 yards per rush. That type of run defense allows the team to focus on stopping the pass, without having to stack the box. But how do these numbers compare to some of the great defenses of the past?

The 1985 Bears allowed 4.4 per play, and over 6 yards per pass, yet just 12 points a game. The 2002 Bucs were stingy on the scoreboard as well, giving up 12.2 a game. Yet the only defense that comes close to this year's is the Steel Curtain defense of the 1976 Steelers: 3.8 yards per play, 5.8 per pass, 3.2 per run.

If the 2008 Steelers continue like they have so far, especially against the Cowboys, then they could go down as one of the greatest defenses ever. Allowing these numbers in a day and age when offenses are scoring at historical rates, allowing under four per play is...well....I don't what the word is......outstanding just doesn't seem to fit.

Bottom line: Can the Cowboys beat this all-time great defense?

Of course, any team can win on any given Sunday.

Yet these numbers show that the Cowboys have a GREAT chance of doing just enough to win. The Steelers have yet to face an offense as prolific as the Cowboys (I know the Giants rank No. 1 in the league, but Tony Romo trumps all), with as many weapons as the Cowboys have on their side of the ball. When the Steelers have faced a quarterback who throws accurately downfield and avoids the rush, then the team struggles to win.

This Steelers team relies on its' defense to set up the offense, to put them in good position to win. The offense itself won't score a bunch of points, but if the defense is able to constantly hold opponents back and turn field position, then the Steelers are adept at taking advantage.

They, like always is limiting mistakes and turnovers. Yet this is even more important playing against a defense like this. No bad penalties, no forced throws. If the Cowboys are able to consistently move the ball without turning it over, then anything more than 17 points should be more than enough to win this game.