Sports - Zero Sum Games?

Are sporting contests zero-sum games? That's a description I find a lot when it comes to talking about the sort of competition that occurs on the playing field. Russell Roberts at Cafe Hayek refers to this sort of competition as such.

I don't think that sporting contests are zero-sum games in many instances. For instance, consider today's Kansas at Missouri men's basketball contest in Columbia.

Missouri needs this one more than Kansas. There should be a difference between playing for your competitive life and playing for a No. 1 NCAA seed, which Kansas might not get even with a victory at MU.

Sports are zero-sum games if we narrowly define the outcome as a win and a loss and assume that the value of a win equals the value of a loss for each team. But that's a big assumption to make in many cases.