I know both teams are built and operating a bit differently now than they were when they played in September but I think Ohio State would be in a good position to win a rematch. It would also add an interesting wrinkle to the playoff that I don't think we've seen so far (correct me if I'm forgetting a former playoff rematch).
Based on current rankings I think the only way it could happen is if Oregon and Ohio State can get to #2 and #3.