It isn't the grass you should worry about, it's going up against a decent offense without your best WR....
USC's third WR is better than Washington State's first WR. That's no reason to be cocky, but if USC gets upset this year, it's surely not going to be by Washington State.
Cal, Arizona State, maybe even UCLA are bigger obstacles. The Notre Dame game always looked like a big one, especially after that game for the ages last season, but Notre Dame isn't scaring anyone right now.
But that matchup is the last game of the season, and the landscape will probably look much different than in September.