Xs and Os on Saturday's Texas-Oklahoma's showdown from the proprietor of the essential Smart Football.

It's difficult to find much fault with Oklahoma's offense in last year's back-and-forth, surprising 45-35 loss to Texas. If anything, the burden fell on Bob Stoops' defense: Longhorn quarterback Colt McCoy carved up the Sooners with his usual deadly precision, with UT receivers Quan Cosby and Jordan Shipley each hauling in more than 100 yards receiving and unsung running back Chris Ogbonnaya adding 127 yards on the ground. On the other side, McCoy's counterpart, Sam Bradford, passed for 387 yards and five touchdowns (with two interceptions); 35 points ultimately matched OU's regular season low for the year, but under any circumstances should still be enough to win, maybe even when the opposing quarterback's gutsy performance is thrusting him to the front of the Heisman race.

But it's possible to find fault with the Sooners' offense that afternoon, namely in the running game, which pounded out just shy of 200 yards on 4.7 per carry and produced two 1,000-yard rushers for the season but only managed a meager 48 yards on 26 carries against Will Muschamp's defense in Dallas. This was something of a theme: The OU running was only held in relative check three times in '08, and two of those were on the team's biggest stages, in the losses to Texas and Florida. (TCU also went all-out to shut down the Sooners on the ground, but forfeited 411 yards and four touchdowns passing in the effort.) So the run game is quite important to making this vaunted offense go, regardless of who's in place at quarterback.

Before the '09 season, much was made about the massive turnover on OU's offensive line. So far, though, even in the losses to BYU and Miami, the run game has held up well -- veteran backs Chris Brown and DeMarco Murray are just a shade off their '08 pace, combining for 150 per game on just shy of five per carry. Aside from Bradford's shoulder injury, it seems the bigger issue for OU has been the loss of Bradford's top five targets from last year, including injured Jermaine Gresham, who won't be back, and Ryan Broyles, who might be back as soon as Saturday. The upshot, with a gimpy Bradford and a still depleted receiving corps, is that the burden falls on Murray and Brown to redeem their poor performance against Muschamp's unit last year.

Spreading and running, and Stoops' soul searching. When Oklahoma's offense is rolling, as it was most all of last season, it is a thing of beauty: One play the Sooners line up with four receivers, then come out with a tight end and fullback the next. They can run the ball out of spread sets where the running back motions from the slot into the backfield, or where Bradford tosses the ball back to a more traditional I-back. And they do it all from a high-speed, no-huddle tempo that discourages substitution by the defense and ultimately mows then down.

The machine falls under the authority of Kevin Wilson, offensive coordinator and architect of the Sooner ground game. Before accepting Bob Stoops's offer to come to Norman in 2002, Wilson was a longtime protégé of the late Randy Walker, both at Miami of Ohio and, quite memorably, Northwestern. Walker and Wilson came up as smash-mouth, power football guys, steeped in lots of I-formation and other two-back sets with power leads, isos, counters and the like. But when they arrived at Northwestern in 1999, it quickly became apparent that their personnel there was not going to win too many games by trying to run over Big Ten defenses designed specifically for straightforward, old-school slugfests.

The Wildcats took note of the success Joe Tiller had at Purdue with a spread-to-pass strategy against such defenses, but they needed their own spin. Walker and Wilson met with Clemson's offensive coordinator (some guy named Richard Rodriguez), and saw that they could line up in the shotgun with spread sets -- thus forcing the defense to substitute out of its base defense and often align rather simply -- and then run the same power plays at the spread-thin fronts. The knock on the shotgun had been that the running game was limited' maybe you had a base run and a draw, but that's it. Running the same plays from the gun was Walker and Wilson's key insight: Instead of being limited to the old Run 'n Shoot finesse, a whole world of possibilities opened up, and they began by drawing up their same playbook, with the same blocking schemes, in a variety of new sets. And the result was historic (albeit brief), culminating in Northwestern's famous 54-51 shootout victory over Michigan in 2000. The Wildcats threw for over 300 yards against the Wolverines -- typical stuff for a spread team in victory -- but what caught the eye of coaches around the country was the fact that outmanned, overpowered Northwestern had also managed to rush for over 300 yards in the same game.

Over in Norman, Stoops had a bit of a dilemma. He took over Oklahoma in 1999 and brought on an oddball assistant coach from the University of Kentucky to coordinate his offense. Stoops, in his prior role as defensive coordinator at Florida under Steve Spurrier, felt that the only team that had an incommensurate level of success against his Gator defenses in terms of its talent level was Kentucky. OU managed to make a bowl game that year, and the offense improved dramatically. That offensive coordinator, Mike Leach,left to take the top job at Texas Tech, as you may recall. Stoops elevated his offensive line coach, Mark Mangino, to the offensive coordinator role. In 2000 OU ran Leach's Airraid offense with only minor adjustments (and, most importantly, Josh Heupel, the same quarterback), and won a BCS title. Stoops, however, was not a guy content to run an offense with little running threat. He and Mangino then began tinkering with the offense, but overall retained Leach's original framework. Mangino left that season to take over the job at Kansas, and Stoops found himself with a gaping hole in his coaching staff and a run game he was dissatisfied with.

Enter Kevin Wilson. In 2002 Stoops actually hired Chuck Long to be his offensive coordinator and quarterback coach, but Wilson came from Northwestern for the very purpose of bringing his early "power-spread" ideas to OU. Over the last few years, the Sooner offense has evolved into a beast behind Wilson's philosophy, climaxing last season with the highest-scoring offense of all time.

Obviously Sam Bradford's excellence has been a huge part of that emergence, but the often overlooked running game has been frequently dominant, even after Adrian Peterson left for the NFL -- in fact, they've been better on a per-game basis each of the last three seasons than they were in Peterson's last two. But no one who watches OU would say Wilson is running the same spread offense that Rich Rodriguez ran at West Virginia, or currently runs or Michigan, or that Wilson ran at Northwestern (nor, for that matter, what Mike Leach or Mark Mangino do in their schemes). How has the Sooner running game evolved?

Runners in disguise. As dizzying as it can seem, Oklahoma's ground attack is based off basically three plays -- the inside zone, the outside zone and the power, with a few others sprinkled in for good measure. The zone plays give OU the most flexibility: The linemen keep the same blocking schemes, regardless of how many tight ends or wide receivers they use. The aiming points for the backs remain about the same. The Sooners tend to begin with a focus on the outside zone, but once the defense flows too fast to the sideline, they hit them inside.

On outside zone plays, the "covered" offensive linemen (those with a defender lined up directly in front of them) will take a little bit more of a lateral first step and try to "reach" the defender -- that is, get their body in position to seal the defender from chasing the ball outside. The running back aims for a point outside the tight end, though he can cut it upfield wherever a seam appears.

Once the defense begins flowing too fast to the sideline, Wilson will come back to the inside zone. The rules are the same -- covered and uncovered -- except this is more of a drive block as the aiming points are inside. The play often results in a cutback if the defense is flowing fast for the outside zone, but the difference between the outside zone is one of technique, not assignment. And, again, it does not make a difference to the linemen (or at least not much of one) if OU runs this from a four wide set or a two-back one.

The "power" is a bit more complicated but not much more so. It's not a zone play at all: The linemen all block down -- meaning they step away from where the play is going -- to crush the defensive linemen and get double-teams. The offense makes up for this by using the fullback to block the defensive end from the inside-out, and they block the linebacker on the play side by pulling the backside guard.

The beauty of this, however, comes in the execution and tying it all together: OU is still maybe the best example of a "pro-style" offense, but not in actual fact (the NFL is often boring), but in an aspirational sense. At its best, OU's multiple, balanced, fast tempo, no-huddle offense is what NFL teams ought to be running.

It hasn't always been so pretty this season, however, as Stoops' troops stand at 3-2 -- with just 13 and 20 points, respectively, in those two losses, fewer points combined than they scored in any regular season game last year -- and in desperate need of a win against Texas to get the Big 12 championship track alive. If they have a prayer against McCoy and Co., the Sooners will have to stop Texas' lethal passing game, and of course Sam Bradford will have to play like his old, Heisman-collecting self, which will require some of his very green receivers to step up in the biggest game of the year. But the run game is the catalyst for that offense -- it sets up the no-huddle tempo, it sets up the play-action that forms the basis of much of the passing game, and it wears down and seals the fate of an opponent bludgeoned by a steady does of fresh legs throughout the game. If the Sooners want to take back the Red River Shootout, it will begin with DeMarco Murray, Chris Brown and the much-maligned Oklahoma offensive line.

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Chris Brown writes the strategy and philosophy site Smart Football and also contributes to the New York Times' Fifth Down blog. You can reach him at chris at smartfootball.com, or follow him on Twitter.