IMHO, Ohio State's 4-week run at #1 is in very serious jeopardy this weekend for at least three reasons:
First, I think that Washington is a pretty good team. Vegas has the Buckeyes as a 9.5 point favorite, that is a legitimate game.
Second, I don't think that the AP Voters respect Washington nearly as much as they deserve and as Vegas does. As only a 9.5 point dog to #1, UDub should be ranked or at least getting some votes but they aren't. Thus, I'm thinking that if Ohio State wins by roughly the spread (say 8-12 points) the AP voters will see it as a bad thing. Even if Ohio State wins big I don't think they'll get much credit from the AP voters for it so basically this game is one of those everything to lose, nothing to gain situations for the Buckeyes.
Third, at least one and possibly several teams close behind the Buckeyes will get a big quality win this weekend. #2 Miami is off but #3 Penn State hosts #6 Oregon. That pretty much hurts the Buckeyes either way. LSU is an underdog at Ole Miss so a big win would get them a bunch of first place votes. Georgia plays Bama so they would pick up first place votes with a win as well.