This is one of those no-win situations for both teams.
Oregon wins, and people will say they should have won. No big deal. Everyone says that Oregon wouldn't make it in the SEC. Yet, they've beaten Tennessee and Mississippi State twice in the last decade. They lost to Auburn and LSU, but so did everyone else those years because those teams were really talented and championship caliber. So what is it? Oregon wouldn't make it in the SEC. Yet we beat a few SEC teams and people say, "Well those wins don't count because those teams aren't any good."
Tennessee wins and they have to put together a really good season for it to mean anything. If they lose to Florida, Georgia, and eUSC after beating the Ducks, people will say, "Well it was a fluke - an aberration." It'll be considered an upset because that's what an upset is: a team that really shouldn't have won, wins.
It sucks. The way I see it, these are two good teams, especially Oregon being ranked #2, and the win should mean something no matter what happens. Tennessee is good. I think the 27.5 spread is crazy. No matter who wins, it should be considered an impressive accomplishment.