Preseason power rankings: Big 12 touts big three at the top in Oklahoma, Iowa State and Oklahoma State

This story is part of USA TODAY Sports' 25 days to college football countdown.

A fixture in the race for the College Football Playoff, Oklahoma's championship hopes feel even more legitimate thanks to the growth of a defense that is suddenly an asset, not a liability.

Last season saw the Sooners hold five straight conference opponents to 400 or fewer yards of offense, the program's longest such streak since 2012. After giving up 40 points per game against its first three Big 12 foes, OU allowed just 17 points per game and 4.2 yards per play in closing 7-0, capped by a 55-20 win against Florida in the Cotton Bowl.

It's a simple formula: OU's offense, plus this defense, makes the Sooners tough to beat. One Big 12 team that may disrupt that equation is Iowa State, the No. 8 team in the preseason USA TODAY Sports AFCA Coaches Poll and a national championship contender in its own right. These two teams top the preseason Big 12 power rankings.

1. Oklahoma (2020 record: 9-2)

That last year's finish is viewed as a slight disappointment speaks to the standards in place under coach Lincoln Riley. With the nation's top quarterback in Spencer Rattler to go with that reborn defense, OU has the parts needed to reach the playoff and beat Clemson, Ohio State and the best the SEC has to offer.

2. Iowa State (9-3)

The perception of ISU as a bunch of plucky underdogs maximizing its talent behind superb talent development and execution is only slightly correct. The Cyclones are far more talented than most people believe, with several players ranked among the nation's best at their positions and perhaps a dozen or more players heavily in the mix for all-conference honors. In other words, this is a team with the roster to match its preseason ranking and compete for the title.

3. Oklahoma State (8-3)

The baseline should be set at a Top 25 finish. Should even more be expected? It'll be hard to crack into the top two given the teams in place at OU and ISU. But the Cowboys' defense has made huge strides since 2018 and the offense is ready to roll at quarterback, running back and the line. OSU does need to develop two or more go-to receivers, however.

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4. Texas (7-3)

There are loads of top-tier recruits on the roster and, in coach Steve Sarkisian, a leader with a track record to suggest he can develop an explosive offense. One of the obvious beneficiaries of Sarkisian's arrival is sophomore running back Bijan Robinson, a preseason USA TODAY Sports All-America pick. 

5. West Virginia (6-4)

There is a whole lot to like about WVU, which might be an improved running game away from making a serious run at third place in the Big 12. As average as the ground attack was in 2020 (3.8 yards per carry), that was a marked improvement over 2019, coach Neal Brown's first year, when the Mountaineers ranked 129th nationally in yards per carry and 128th in yards per game.

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6. TCU (6-4)

Getting a healthy and complete season from quarterback Max Duggan is mandatory should TCU look to reverse three years of relative mediocrity under coach Gary Patterson and crack the 10-win mark. The potential is there, especially given the state of a defense that should challenge OU and WVU for the title of the league's best. The schedule is unkind, however, with trips to Norman, Oklahoma State and Iowa State.

7. Kansas State (4-6)

The room for error is small, and not helped much by non-conference games against Stanford and Nevada. One key to improvement in coach Chris Klieman's third year is the health of quarterback Skyler Thompson; the Wildcats are a different team with him in the lineup. The offense also has an outstanding all-around weapon in second-year running back Deuce Vaughn.

8. Baylor (2-7)

Three easy games to open the year — Texas State, Texas Southern and Kansas — should provide the Bears with a needed dose of optimism after winning just twice in 2020. But is there enough here to climb out of the bottom third of the conference? It depends on your faith in second-year coach Dave Aranda and new offensive coordinator Jeff Grimes, who has the task of improving last season's putrid attack.

9. Texas Tech (4-6)

In a strange shift, concerns over this year's team focus far more on offense than with the defense, which brings back nine starters and a healthy portion of last year's two-deep. The offense has regressed in each of coach Matt Wells' two seasons but could be sparked by a return to the pass-happy style embraced by coordinator Sonny Cumbie. 

10. Kansas (0-9)

Kansas is bad enough to defy description. But there is hope in the form of new coach Lance Leipold, a proven winner drawn to the sort of massive building project necessary in Lawrence. Just be patient.

Follow colleges reporter Paul Myerberg on Twitter @PaulMyerberg