I suspect our definitions of average might be fairly different. The average salary for a player in BuzzerBeater is currently 3342. This will not change very much.
Maybe just a suggestion. How about, when the allstar break comes closer, have a new player value. His "expected salary next season". This could be only visible by the team owner and when the player hits the TL. It would give every team a better idea of what is coming.
I don't think there's a better way to answer this, because it really does depend upon training patterns and so forth.