I actually think Ohio State has a better chance to get in than it may look, BUT I don't think it ultimately happens.
Ohio State got blown out by Purdue and had two very close wins against Nebraska and Maryland. I think Notre Dame is a lock so long as they take care of business vs. USC tonight. Clemson is very likely to get in unless Pittsburgh beats them, but I doubt that.
The main problem I see is that, even if Alabama loses to Georgia, there's a chance they still keep Alabama in the playoffs as a 4 seed possibly, and so both OU and OSU get screwed in that case. If Alabama wins, then it's one spot left likely between OU and OSU, and I think they give it to OU especially if they beat Texas next weekend.
Basically, Ohio State has to take care of business next week against Northwestern, and then hope Alabama wins AND one of Clemson/Oklahoma lose in their conference title games next week (or USC upsets Notre Dame tonight).
And btw, I think Notre Dame is overrated and Clemson, while proven in the past, have had some really close games against currently ranked teams that could have gone either way (Syracuse and Texas A&M, both ranked 20 and 22 respectively, and Clemson won both games by less than 5 points). They did have an impressive win against #17 ranked BC a few weeks ago, but BC is now 7-5... so BC may have been overrated anyways.
Oklahoma's offense is electric/dominant but their defense is pure garbage. But you can't count them out IMO either.