I think substance abuse should probably be handled the same way you'd handle a frayed rotator cuff or a groin pull.
I understand that this would never happen. Ever. I know that going on the DL for being a drunkard is pretty far-fetched. And you know what? Many, many injuries are kept secret anyway.
You can't prove that someone is an alcoholic with an x-ray or an MRI. But let's say you're Mike Scioscia... damn sure you know who all your drunken fuck-ups are. He might even have to bench a guy!
My point is this: If you're playing fantasy baseball, you might think twice about drafting a guy with a history of arm trouble or something. But no stat website or scouting report is going to say KEVIN CASH SERIOUSLY CANNOT STOP DRINKING AND IT'S AFFECTING HIS CATCHING ABILITY ... or... COKE AND HOOKERS HAVE CAUSED COLBY RASMUS TO BLOW OFF CONDITIONING AND FIELDING PRACTICE!!!
How about CRYSTAL METH AND SCHNAPPS HAVE TURNED ADAM WAINWRIGHT'S BRAIN INTO MUSH!!!
(I'll state the obvious and say these are fictional scenarios.)
Why is it considered poor taste/judgement to say "Boston should not accept a trade for Player X because he refuses to go to rehab"? That sort of thing will get you eviscerated on a message board! And what if you're on the receiving end end of such a trade? Does the originating team have an obligation to report these things?
Should the Mariners say "We agree to this trade; however, be warned that Minor League Sam parties waaaaay too much and he is disinterested in coaching/training advice."?
I'll bet everyone knows who has problems, anyway. Baseball players talk shit about each other endlessly. Word travels.
I asked one person about this situation and they said that substance abuse information can wind up on medical records. Team doctors have access to this stuff even if GMs do not.
Substance abuse can be as much an impediment to performance as a physical injury. If I want to make informed decisions when playing fantasy baseball, that kind of information would help.