Also, Stephon Marbury came out of a one and a half year hiatus to play for the Celtics and is not nearly as productive as he was. And I don't think that should be surprising. If you don't play NBA level basketball, or any level basketball, for 18 months, you can't come back and be an impact player as a guard. Maybe a big man could do it, but not a small player who relies on quickness, speed, and shooting touch/shooting confidence.
Are there counter examples? BR article, perhaps?