Assuming Alabama, Georgia, & Clemson all finish with 1 loss or less, they will all get it.

BYU would then have to beat out the Big 12, Big 10, and PAC 10 champions plus any name schools with otherwise good resumes (ie, 1 loss Ohio State/Penn State/Miami, etc). I don't see that happening unless there are no other P5 teams with 1 or fewer losses. Even then, I think the committee & media would push very hard for the P5 team.