Look, we all know that some athletes have taking banned substances or steriods (even if not banned by MBL at the time) or illegal drugs from time to time. It is wrong and the players know it. If they get caught and agree to seek professional help and follow through, they should be given every opportunity to keep their career alive. Case in point Santino Quaranta for DC United.
But if the player refuses professional help and/or refuses to follow through on that help, the the club/team should fire them. Well PSV Eindhoven in the Dutch Eredivisie (First Division) have fires striker Jonathan Reis after positive test for a banned substance.
Good. The quicker the punishment is meted out and publicly to the extent necessary--the better. Banned substances, whether illegal drugs or performance enhancing substances should be swiftly and immediately punished.