It's not too hard to drum up scenarios where 12-1 BYU is bumped by 2-loss SEC or Big Ten teams.
1) Oregon 13-0
2) Tennessee 12-1
3) Clemson 12-1
4) Colorado 11-2 or Texas Tech 10-3
5) Miami 12-1
6) Penn State 11-1
7) Notre Dame 11-1
8) Texas 11-2
9) Ohio State 11-2
10) Boise State 12-1 or Army 12-1
11) Indiana 11-1
12) Georgia 10-2