ESPN

This week's Power Rankings feature a new No. 1, as last week's No. 1 takes a tumble:

1. Oklahoma (4-0, 1-0 Big 12, last week 3): The Sooners take over the top spot after delivering the most impressive Big 12 win of the season. Notre Dame is not the same team as last season, but the Irish hadn't lost in South Bend since October of 2011. OU has been a different team since Blake Bell took over at quarterback, and Bell was fabulous Saturday, throwing for two touchdowns without a turnover while churning out first downs with his arm and his legs. The OU defense is clearly better, too, picking off QB Tommy Rees on Notre Dame's first two possessions, with linebacker Corey Nelson returning one for a touchdown. The Sooners were clearly a team overlooked in the preseason, and, after five weeks, are looking like a clear Big 12 favorite along with Baylor.

2. Baylor (3-0, 0-0 Big 12, last week 2): After the off week, the Bears' offense will get its first real challenge this weekend from West Virginia's defense that appears to be the most improved unit in the league. Baylor has been unstoppable so far, but the level of competition is about to undergo an uptick. Can the Bears keep it up? They've shown no signs they can't.

3. Texas Tech (4-0, 1-0 Big 12, last week 4): Despite having the week off, the Red Raiders move up a spot with Oklahoma State's loss. The big question in Lubbock is who will be starting at quarterback for Tech come Saturday against Kansas. Baker Mayfield? Davis Webb? Michael Brewer, who has been progressing well from the back injury? The Red Raiders have been solid defensively, and the skill talent is legit. If Tech can get better play from its quarterback, this team could be a handful -- even for OU and Baylor.

4. West Virginia (3-2, 1-1 Big 12, last week 8): What a difference a week makes. The Mountaineers produced the most impressive in-conference win of the season with a 30-21 victory over preseason favorite Oklahoma State. West Virginia's defense continues to play at a high level (Maryland's 37 points were somewhat of an anomaly because of West Virginia turnovers) and Clint Trickett sparked the offense with his energy and leadership. West Virginia's offense is still pretty limited, but at least it no longer looks completely inept with Trickett at quarterback. The Mountaineers can't score with Baylor this weekend, but maybe they can slow the Bears down? Nobody thought West Virginia could slow Oklahoma or Oklahoma State, either, though Baylor's offense is at another level. We'll see.

5. Texas (2-2, 1-0 Big 12, last week 5): The Longhorns have a couple of interesting games looming. Thursday, Texas travels to Iowa State, which looked much better offensively in a 38-21 win at Tulsa this past Thursday. Then, Texas gets surging Oklahoma in Dallas. This figures to be the defining two-game stretch of the season for the Longhorns. Win the next two, and the season -- as well as Mack Brown's status in Austin -- looks totally different than it did two weeks ago. The off week could not have come at a better time for the Longhorns, giving acting defensive coordinator Greg Robinson another week to acclimate to his defense and quarterback David Ash another week to recover from the head injury that knocked him out of the Ole Miss and Kansas State games.

6. TCU (2-2, 0-1 Big 12, last week 6): Did TCU's offense finally uncover an identity during a rainy fourth quarter against SMU? The Horned Frogs poured on 31 points in the final quarter and did it with some new faces, as Ty Slanina, Ja'Juan Story and Cameron Echols-Luper all factored into the scoring onslaught in the first real action of their TCU careers. The Horned Frogs can really turn their season around with a win in Norman this weekend. That won't be easy, though, if All-American cornerback Jason Verrett (shoulder) and defensive end Devonte Fields (foot) can't play.

7. Oklahoma State (3-1, 0-1 Big 12, last week 1): The Cowboys plummet six spots after an uninspiring performance in Morgantown. It was just one loss, but it was a loss that exposed weaknesses across the board. For the first time in seemingly forever, Oklahoma State's kicking game is awful. The Cowboys' secondary gave up 320 yards to a West Virginia passing attack that previously had been completely futile. And on the other side of the ball, when the Mountaineers dared QB J.W. Walsh to beat them deep, he couldn't do it. That allowed West Virginia to stuff the Cowboys' running game, which also doesn't appear to have that bell-cow running back Oklahoma State has been accustomed to featuring. The Cowboys are better than they looked at West Virginia -- but how much better?

8. Kansas State (2-2, 0-1 Big 12, last week 7): Bill Snyder maintains the Wildcats will stick with the two-quarterback system, which has yielded mixed results. K-State has moved the ball better when Daniel Sams has been in at quarterback. But when he's in, the Wildcats are virtually no threat to pass. Sams has 29 rushes and only four passing attempts. Is Sams really that poor of a passer? Maybe it's time for K-State to find out.

9. Iowa State (1-2, 0-0 Big 12, last week 10): It's hard to believe a center could make that much of a difference. But the return of Tom Farniok sure seemed to do wonders for Iowa State's offense, which finally got going in a 38-21 win at Tulsa. The Cyclones also finally involved running back Aaron Wimberly, who ignited the running game with Iowa State's first 100-yard performance in more than a year. With former blue-chip junior-college transfer E.J. Bibbs emerging now at tight end, QB Sam Richardson no longer appears to be on his own. Jack Trice will be rocking Thursday night for the Longhorns, as Iowa State has a chance to land a signature win to build off of for the rest of the season.

10. Kansas (2-1, 0-0 Big 12, last week 9): The Jayhawks have a winning record but have been mostly unimpressive. Can they turn around the offense against Texas Tech? That will hinge almost entirely on quarterback Jake Heaps, who has talent but has been unable to find any rhythm so far with a collection of unproven wideouts. If the Jayhawks can be competitive this weekend, it will be a good sign they are moving in the right direction. If they get blasted, it could be a long season, especially with Iowa State and West Virginia seemingly having found their stride.

There's no crying in baseball, but I guess it's OK here.

• The Cyclones found their footing, and an offense, at Tulsa, according to the Ames Tribune's Bobby La Gesse. Tommy Birch of the Des Moines Register writes about how QB Sam Richardson overcame injuries to guide Iowa State to the 38-21 win. The paper's Bryce Miller explains how center Tom Farniok shored up the Cyclones offensive line.
• Saturday, Clint Trickett will become West Virginia's third starting quarterback already this season. The Charleston Daily Mail's Mike Casazza breaks it down. The Mountaineers are also ready to pick up the pace, writes Dave Hickman of the Charleston Gazette. Opposing defenses, meanwhile, have the blueprint for stopping the West Virginia offense, in the opinion of Stephen J. Nesbitt of the Pittsburgh Post-Gazette.
• The Sooners are expecting a big-time atmosphere in South Bend. The Oklahoma players talk about playing in big-time games. The Oklahoman's Jason Kersey breaks down the OU-Notre Dame matchups. The Dallas Morning News does the same.
• Oklahoma State offensive coordinator Mike Yurcich is getting the opportunity of a lifetime, writes The Oklahoman's Gina Mizell. Running back Jeremy Smith has been a reason for Oklahoma State's 3-0 start.
• Baylor coach Art Briles is hoping his book, “Looking Up: My Journey from Tragedy to Triumph," inspires. The Bears expect to get back tight end Jordan Najvar and running back Glasco Martin next week in their Big 12 opener against West Virginia. The Dallas Morning News compares the Baylor and Oregon offenses side-by-side.
• TCU is the best in the Big 12 when it comes to non-conference scheduling, according to The Oklahoman's Ryan Aber. The Horned Frogs need an offensive spark, according to the Fort Worth Star-Telegram's Jimmy Burch and Stefan Stevenson. E.J. Holland of the Dallas Morning News predicts the Frogs will keep the Iron Skillet in Fort Worth.
• The Lawrence Journal-World's Matt Tait writes that the Kansas offensive line is trying to get tougher during its open week.
• A bye week on the schedule doesn’t mean Kansas State has taken it easy, either, according to Ken Corbitt of the Topeka Capital-Journal.
• Texas Tech is planning some reunions.
• Could there be crimson on the burnt orange side? The AP reports that Texas students have not claimed all their tickets for the Red River Rivalry.

Our guest picker this week is Omar Ahmad, out of Huntington, W.Va. Here was Omar’s clever submission:

I should be your Big 12 guest picker for Week 5. Why? Because when it comes to challenging the experts at ESPN, nobody Bears down like I do. I'm like an unstoppable Cyclone of correct predictions. I'm not a Wildcat with my selections (you'll never catch me picking a Longhorn to do anything other than be a horn that's long). I strive for the highest summits of analysis the likes of which no Mountaineer has ever seen. While you may be a college football maverick, I'm the Red Raider with guns-up accuracy. No Jayhawk can hang with my stuff (or anyone's stuff, for that matter). So stop being a Cowboy with your reckless game-picker selections. You know you're gonna tab me Sooner or later. Horned Frogs.

Last week, I correctly picked Texas to bounce back and beat Kansas State, but Omar’s Mountaineers burned me with a no-show performance in Baltimore. I was also called out in front of my ACC colleagues via this tweet from a @beedubss: “I hope Andrea Adelson and Heather Dinich get to give @ESPN_Big12 a really hard time about his #WVUvsMD prediction. #GirlsRuleBoysDrool #GoTerps”.

Come on, guys. We’re better than this.

If you want to be next week’s guest picker, contact me here, and tell me why. And, as always, creativity counts.

To the Week 5 picks:

SEASON RECORD

Trotter last week: 4-1 (.800)

Guest picker last week: 4-1 (.800)

Trotter overall: 25-5 (.833)

Guest picker overall: 10-3 (.769)

Tulsa 30, Iowa State 27: Dating back to last year, Iowa State has now lost six of seven, which includes a two-touchdown loss to Tulsa in the Liberty Bowl. Tulsa, meanwhile, has played better since an embarrassing 27-point loss at Bowling Green in its opener. This game is in Tulsa, where the Hurricane has not lost since falling to eighth-ranked Houston in November 2011. The Cyclones just don’t have the offensive firepower right now around quarterback Sam Richardson, who also faces the possibility of playing the rest of the season on a bum ankle.

Omar’s pick: The Golden Hurricane is a young team, but can still run the ball. The Cyclones cannot, and the return of Tom Farniok won’t change the fact that Sam Richardson is currently the team’s biggest threat on the ground. Tulsa, 31-27

TCU 31, SMU 16: Coach Gary Patterson rode his team hard during the off week, even calling them out in the media for “feeling sorry for themselves.” Despite the disappointing 1-2 start, the Horned Frogs have too many veteran players to feel sorry for themselves for very long. This is still a good team, with good players on both sides of the ball. If TCU can uncover an offensive identity post QB Casey Pachall -- perhaps running the ball more with B.J. Catalon and Waymon James to take pressure off QB Trevone Boykin -- the Frogs will be fine. This SMU game is a golden opportunity for TCU to figure out some things before going to Norman next weekend.

Omar’s pick: Despite the 1-2 start, TCU’s defense is still arguably the best in the Big 12. Garrett Gilbert will get his yards, but Boykin and Catalon run wild on a Mustang front seven that’s one of the smallest and most inexperienced in the nation. TCU, 36-20

Oklahoma State 42, West Virginia 14: Both teams are running Dana Holgorsen’s offense. Only one is running it well. After the 37-0 loss to Maryland, Holgorsen rightfully called West Virginia’s offense as inept as it could be. Omar's Mountaineers don’t have any playmakers at receiver, the offensive line is not getting any push in the run game and QB Ford Childress is too young to overcome either deficiency. Poor Charles Sims, by the way, picked the wrong year to transfer. Imagine Sims on the same team with Geno Smith, Tavon Austin and Stedman Bailey. Now that would be an offense that could outscore Oklahoma State. This West Virginia offense cannot.

Omar’s pick: The Cowboys are getting it done by land and air so far, while the Mountaineers are trying to rebuild the offense through Ford Childress. The WVU defense keeps it closer than most expect. OSU, 34-21

Notre Dame 24, Oklahoma 21: The Sooners feel good about themselves after Blake Bell’s performance against Tulsa. But this isn’t Tulsa. And this game won’t be played in Norman. The Irish have looked lackluster so far this season, but they’ve played a difficult schedule featuring Michigan and Michigan State. The Sooners, meanwhile, have yet to play anybody. Notre Dame will win the battle in the trenches, force Bell into a couple of critical mistakes in his first start on the road and make the plays in the fourth quarter like it did last year in Norman. They will move to 10-1 all-time in the series while preventing the Big 12 from picking up its first Top 25 non-conference victory.

Omar’s pick: Blake Bell has a cool nickname; Tommy Rees does not. OU, 28-23

We'll move on to the cornerbacks today in our position rankings across the Big 12.

Here's what we've covered so far:

• Quarterbacks
• Running backs
• Receivers/tight ends
• Linebackers
• Safeties
• Cornerbacks

This group is subject to more change during the season than perhaps any other position. You never quite know how chemistry will develop, and in these rankings, you really have to rely heavily on experience, similar to quarterbacks. It's not the only factor, but you have to acknowledge that it's a major one.

So, here's how I rank them:

1. Oklahoma State: This is a no-brainer. The Cowboys broke in four new starters last season, but became a big reason why OSU's offense was one of college football's best. Despite throwing 532 passes, third-most in the Big 12, the group surrendered just 10 sacks. All five starters return, too. Running back Kendall Hunter also rushed for more than 1,500 yards. Right tackle Levy Adcock headlines the unit as the league's best overall lineman.

2. Baylor: The Bears might be a bit of a surprise here, but Baylor's strong skill-position talents wouldn't look nearly as good without this group, which lost a first-round pick at left tackle in Danny Watkins. However, Philip Blake is one of the league's best centers and four starters return from a line that helped Baylor finish second in the Big 12 last season in yards per carry, just behind Nebraska but nearly a half-yard more than Oklahoma State, the third-place team.

3. Missouri: The Tigers suffered a big loss in center Tim Barnes, a three-year starter and the offensive line's leader, but they return four starters from last season line and have the most career starts on the line of any team in the Big 12, with 105, which ranks 11th nationally.

4. Texas A&M: A&M's rising sophomore tackles, Luke Joeckel and Jake Matthews, had to learn on the go last season, but their development should be fun to watch this season on an offensive line blocking for the Big 12's best overall collection of skill-position talents. The line returns four starters, replacing only center Matt Allen.

5. Oklahoma: The Sooners' goal-line problems last season cost them a game at Texas A&M, but this line was very solid the rest of the season and has plenty of upside. Likely starter Jarvis Jones won't be available until perhaps October, so the Sooners will turn to touted redshirt freshman Daryl Williams at right tackle in the interim. Center Ben Habern and tackle Tyler Evans add a lot of experience.

6. Texas Tech: Tech boasts one of the Big 12's best guards in Lonnie Edwards, but don't be surprised if Mickey Okafor grabs the Big 12's first-team spot at right tackle by season's end. The Red Raiders return all five starters, and will have to play well to support new faces at every skill position on offense.

7. Kansas: Four of the Jayhawks' starters are juniors and another is a senior, and for all of KU's struggles last season, it did have some success running the ball in spots, even though its 1,615 total rush yards were the fewest in the Big 12. James Sims (742 yards, 9 TDs) returns and KU adds a possible home-run threat in Darrian Miller, but the offensive line returns 97 total starts, 15th-most in college football and second-most in the Big 12. That has to pay off eventually, if not this season.

8. Iowa State: The Cyclones boast the league's best left tackle, Kelechi Osemele, but center Ben Lamaak is gone and ISU might turn to redshirt freshman Tom Farniok as his replacement. Brayden Burris is solid at right tackle, but sophomore Ethan Tuftee, who has very little experience (just five appearances total), enters fall camp as the starter at right guard.

9. Texas: No, I don't know how this happens. But it's hard to deny. Run blocking has been a struggle for Texas, and new position coach Stacy Searels will have to change that for the Longhorns, who have kept quiet about any real depth-chart developments throughout the spring and into fall camp. Tray Allen's health is a concern, but Mason Walters played well in 2010 and David Snow has a lot of experience at center with 19 starts and 39 appearances. If this group can't ascend in these rankings during the season, Texas' turnaround from last season 5-7 campaign will not happen. Texas, though, has the fewest career starts in the Big 12, with 36, which ranks 105th nationally.

10. Kansas State: Kansas State has had the Big 12's leading rusher the past two seasons, but he's gone and so are three offensive linemen, including the unit's best blocker, guard Zach Kendall. Center Wade Weibert and guard Kenneth Mayfield also are gone, leaving gaps in the interior. Senior Zach Hanson joins Manese Foketi and Clyde Aufner on a unit that returns just 42 career starts, second-fewest in the Big 12 and 97th-most in college football.