If we beat Wisconsin, and everyone else wins, I think we are in.
Baylor and TCU are going to cancel each other out. TCU has been ranked higher than Baylor for a while now, but Baylor holds the head-to-head win. So, who do you rank higher in the end?
Also, neither TCU nor Baylor will play a championship game, which I think is the biggest deal when considering where they all land in the final rankings. If the committee is to be believed and have any credibility, they must give at least a little weight to championship games. When they do, then that gives Ohio State the nod.
Also, everyone is kind of down on Ohio State right now because of the uncertainty surrounding Cardale Jones. However, if Ohio State beats Wisconsin, then I'm sure the narrative will be something like, "See, Ohio State just reloads, look at all that talent" and "Cardale almost beat out JT for starter position after Braxton went down, so he has to be pretty good," and "Cardale is the third best QB, but he's backing up two QBs that are legitimate Heisman candidates - thus, how do we know Cardale isn't a Heisman candidate himself?!?" and things like that. Meaning, the win over Wisconsin will take away that uncertainty and give the committee confidence that Cardale can keep the team playing at a high level. If Ohio State loses, well, then that decision becomes all that easier.
The committee will be fucked if Ohio State loses but everyone else wins, as then they'll be forced to pick between TCU and Baylor, and that's a no-win situation for them. Ohio State at the #4 gives the committee an "out" if you will.
Also, like Josh said, this comes down to money in some respects. Don't think the committee isn't wondering how the marquee will look. Ohio State versus Alabama in the first ever playoff game has a certain cache to it - far more than, say, Alabama versus Baylor.