Sure it's not your hub,I had the same concerns recently and could swear it was the bearings and felt like play in the swing arm,turned out the hub had play in it and needed to be rebuilt.
elsinore said:Make sure you check your shock hardware as well. I replace the reducers with the DU bushing in the back of the shock where it connects to the swing link at least every 3 months during the riding season. They wear out pretty quick and develop play you can feel when you lift the back of the bike off the ground.