Looked at the four playoff teams along with Ohio State since they were so close to being in the playoff. Each team's OOC opponents' Sagarin rankings:
Alabama: 100
Clemson: 72.75
Oklahoma: 68.7
Michigan State: 60.75
Ohio State: 89.75
Now, their conference opponents:
Alabama (9): 19.4 (all 9 ranked in top 29)
Clemson (9): 52.6 (2 ranked in top 29, 5 ranked in top 50, all 9 ranked in top 100)
Oklahoma (8): 50.3 (4 ranked in top 29, 5 ranked in top 50, 8 ranked in top 100)
Michigan State (9): 53.7 (3 ranked in top 29, 4 ranked in top 50, 8 ranked in top 100)
Ohio State (8): 58 (2 ranked in top 29, 2 ranked in top 50, all 8 ranked in top 100)