When installing a new chain and sprockets tonight, I noticed my rear sprocket has play in it from front to back (when rotated)...not side to side. I'm guessing this is not normal. Now would that mean I need a new sprocket hub? Looking at the exploded view that seems like that would be it. Anybody ever have this problem?

 

sounds to me like was loose and over time ground out the hub....probably needs to be replaced but im no expert