Let's preview the outlook for the Big 12 this season, according to our Power Rankings:
Last season's record: 11-2
Key losses: RB Joe Mixon, RB Samaje Perine, WR Dede Westbrook
Reason for optimism: No returning FBS QB has more career wins than Mayfield, who will be operating behind an offensive line as stout as any in college football. The defense also quietly improved down the stretch last season.
Reason for concern: Mayfield will be relying on an almost completely new contingent of skill-position pieces. The defensive front seven also has questions, especially at middle linebacker.
Game to watch: at Ohio State (Sept. 9)
Last season's record: 10-3
Key losses: DT Vincent Taylor, S Jordan Sterns, TE Blake Jarwin
Reason for optimism: Rudolph and Washington form the most prolific pass-catching combination in the country. On top of that, Rudolph will have several other dangerous weapons to throw to, including Marcell Ateman, Jalen McCleskey and LSU transfer Tyron Johnson.
Reason for concern: The Cowboys don't have a single cornerback with starting experience in Stillwater. If the other young corners falter, the Cowboys will be scrambling.
Game to watch: Oklahoma (Nov. 4)
Last season's record: 9-4
Key losses: DE Jordan Willis, S Dante Barnett, LB Elijah Lee
Reason for optimism: Bill Snyder almost always outperforms preseason expectations, and the expectations are high for this team. The frontline talent on defense is as good as any in the Big 12.
Reason for concern: The depth along the trenches is thin on both sides of the ball. An injury there could derail the Wildcats.
X factor: Alex Barnes rushed for 298 yards while averaging 8 yards per carry in the brief time he was the primary ball carrier last season. In tandem with Ertz, the Wildcats could have a lethal one-two punch on the ground.
Game to watch: Oklahoma (Oct. 21)
Last season's record: 10-3
Key losses: C Tyler Orlosky, WR Shelton Gibson, CB Rasul Douglas
Reason for optimism: Florida transfer Will Grier could be West Virginia's best QB since Geno Smith, with the ability to stretch the field with a powerful arm. Askew-Henry's return from a knee injury figures to stabilize the secondary.
Reason for concern: The offensive line will be in flux after losing several key players from last season's group. The defensive line is almost completely new as well, and the Mountaineers will be without key linebacker David Long for at least the first month of the season.
X factor: If the spring game is any indication, transfer David Sills could become Grier's favorite target. Sills left West Virginia to try to be a QB again but returned as a receiver, where he's a natural.
Game to watch: Virginia Tech (Sept. 3)
Last season's record: 5-7
Key losses: RB D'Onta Foreman, OG Kent Perkins, QB Tyrone Swoopes
Reason for optimism: Tom Herman has won everywhere he's been, and he inherits a roster loaded with former blue-chip recruits. If Shane Buechele proves to be the answer at QB, the Longhorns are talented enough elsewhere to contend.
Reason for concern: Replacing Foreman's production won't be easy, especially with heir-apparent Chris Warren getting banged up again through camp. Buechele, meanwhile, faded down the stretch last season. If he falters, the Longhorns will have to turn to true freshman Sam Ehlinger.
X factor: After being the Big 12 Defensive Freshman of the Year two seasons ago, Jefferson was a nonfactor last season. The Longhorns need him to be a playmaker, and sliding outside could help in that effort.
Game to watch: Oklahoma (Oct. 14)
Last season's record: 6-7
Key losses: DE Josh Carraway, DT Aaron Curry, S Denzel Johnson
Reason for optimism: This should be another vintage Gary Patterson team, built around depth and versatility. Offensively, the Horned Frogs have weapons, especially if WR KaVontae Turpin returns to his freshman form after an injury-riddled 2016 season.
Reason for concern: QB Kenny Hill led the Big 12 in interceptions last season and was forced into too many negative plays. Turpin's absence through much of spring ball was alarming, as well.
X factor: To reach their potential, the Horned Frogs need Turpin to be the player he can be. When healthy and locked in, he's as electric as anyone in the league.
Game to watch: West Virginia (Oct. 7)
Last season's record: 7-6
Key losses: QB Seth Russell, WR K.D. Cannon, C Kyle Fuller
Reason for optimism: First-year coach Matt Rhule worked magic at Temple and now has more talent in Waco than he ever did in Philadelphia. Sophomore QB Zach Smith is coming off a banner performance in last season's bowl game.
Reason for concern: The Bears are lacking the firepower in the passing game that they have enjoyed in the past, especially at wide receiver. The offensive line is also a problem spot, with few proven commodities.
X factor: As he showed last season, Tony Nicholson can be a game-changer for Baylor on special teams. If he can convert that big-play ability to receiver, it will be a huge plus.
Game to watch: Texas (Oct. 28)
Last season's record: 3-9
Key losses: OG Patrick Scoggins, K Cole Netten, DT Demond Tucker
Reason for optimism: Lazard is one of the top receivers in the country, and the Cyclones appear to be prolific in the secondary and at the offensive skill spots. If Campos can make a full return from a leg injury, the offensive line should be much improved as well.
Reason for concern: The Cyclones have questions on both lines and will be heavily reliant on injury risks and transfers. That could spell trouble.
X factor: After rushing for more than a thousand yards as a freshman two years ago, running back Mike Warren fell out of favor last season. If he can return to form, he'll provide the Cyclones a dynamic wingman alongside starter David Montgomery.
Game to watch: Texas (Sept. 28)
Last season's record: 5-7
Reason for optimism: Despite losing Giles to LSU, the Red Raiders have a fearsome foursome at receiver in Coutee, Batson, Dylan Cantrell and Derrick Willies. Quarterback Nic Shimonek showed potential in limited action backing up Mahomes.
Reason for concern: The defense has been absolutely woeful, with little reason for optimism. Losing Fehoko to LSU didn't help. The Red Raiders will have to hit home runs on their juco transfers, especially in the secondary.
X factor: Linebacker Dakota Allen, recently named a captain, is back from a juco stint after having to leave Tech following a burglary charge. He could give the Red Raiders the sure-tackling inside they desperately need.
Game to watch: Oklahoma State (Sept. 30)
Last season's record: 2-10
Key losses: S Fish Smithson, RB Ke'aun Kinner, WR LaQuvionte Gonzalez
Reason for optimism: The talent level has gradually improved under coach David Beaty, who has outperformed recruiting expectations. Armstrong and Wise form perhaps the top end-tackle combo in the league.
Reason for concern: Washington State transfer Peyton Bender is intriguing, but quarterback is still a total unknown. Losing Gonzalez to dismissal during the preseason was a blow for an offense that hungers for playmakers.
X factor: Alabama transfer Daylon Charlot was one of the most highly touted receivers in the country coming out of high school. Teamed with Sims, the Jayhawks could have their finest receiving duo of this decade.
Game to watch: Kansas State (Oct. 28)