out of conference games (Michigan and Vanderbilt) so may not be interested in other difficult game.
USU is needing a 4th non-conf game, but would have to move its home Idaho St. game on 9/9. Doubt that USU would move their 9/2 game at Iowa.
SJSU and Nevada could also be possibilities if they were willing to move FCS games. This would also be a 13th game on the schedule for them (5th nonconference) which they could do because they play at Hawaii that season.