I am having a hard time assessing who has a better D: Alabama or Oregon. (No that is not a typo.)
If Alabama, this game will be close and you want to take OSU.
If Oregon, then you'd want to favor Oregon -6 (or -6.5 on places like 5D).
Even though Oregon has been whuppin folks lately, OSU is the strongest opponent by far in the last 10 games. (FSU wasn't really a fight. Their schedule made FSU look a lot better than they really were.)