FWIW, the Big 10 changed its rules and allowed tOSU to play in the Big 10 CG. Here is the stated rationale:
"The decision was based on a competitive analysis which determined that Ohio State would have advanced to the Big Ten Football Championship Game based on its undefeated record and head-to-head victory over Indiana regardless of a win or loss against Michigan," the conference said.
Or, put another way, "we know tOSU hasn't played enough games to be a legit candidate for the BCS playoff, and we really want a team in the BCS payoff, so we changed the rules." BTW, not only does tOSU get to play in the Big 10 CG against NW, but they get a week off to prepare while NW has to play Illinois this week.