Sure. Any single season is likely to be a fluke.
If you're given a single die to cast, and you have no idea how many sides are on it, you can roll the die... and get a 7. What is the expected value of the next cast, and what is the number of sides on the die?
Without any additional information, you should probably answer "7" and "13", I would think... it's better than saying any other single number. With a few more data points, though, you can give answers that are more likely to be correct.
In the absence of alternatives, the previous season alone is the best thing to go by. When a track record exists, though, it's easier to argue that a player's production is more reflective of his capabilities and expected contribution to a team.
Ed O.