Rank players of any given sport
Prediction

If the main goal is predicting anything, say, the statisitcs of the player in the next game, game result, then I would not recommend to do any scoring. Better way to go is using the pure statistics data as an input to the model. Any scoring/rankning - is information loss.

Ranking 

If the goal is ranking itself, than you still need to have some target variable to predict. As you may want to check real predictive value of those ranks. That could be, again, playser stats in the next game or game result itself.



References

Sport scores prediction and RFM scoring are probably the next directions for you to look at.