Hard to believe I'm even speculating about this possibility, but I can envision a scenario in which the final four teams are--possibly in this order--Oklahoma State, Alabama, Georgia, and Oklahoma. Here's how it would play out: 

• Oklahoma St. and OU are both undefeated going into Bedlam. OU wins, but since the Big 12 does not have divisions, the Cowboys and Sooners would meet again the following weekend in the conference championship. If Oklahoma State wins, with their sole loss being to a then-undefeated OU, they're in the playoff. And if OU's only loss is to the Big 12 champ--against whom they would also have a win--they might sneak in as the four-seed. Very similar to UGA and Bama both making the playoff in 2018.
• Basically the same thing goes down in the SEC. Alabama beats Georgia to win the SEC, putting the Tide in the playoff. But given how impressive Georgia has been, and the fact that they'll likely be the #1 team in the CFP rankings going into the SEC championship, it's easy to see the committee giving them another shot in the playoffs. 

I don't know if the above would shut the Buckeyes out of the playoff, but I do think the committee would view OU's and Georgia's losses in the conference championships as the "best losses" among one-loss teams in the final set of rankings. Interestingly, this would also set up a string of rematches: depending on how the seeding shakes out, we could see Alabama and Georgia rematched in one semifinal, and OU and Ok. St. would play each other for the third straight game. And assuming Oregon wins the Pac-12, this would likely set us up for a rematch with the Ducks.

Anyway, while I doubt this will end up happening, I haven't seen any speculation about this particular scenario, so thought I'd put it out there. How wild would it be if, after all the talk of the Big 12's demise, they end up with two playoff teams?