Absolutely not a surprise. He and other MLB players and public have probably tried this combination before and got away with it.
His family is blaming the team but drug use/abuse has been part of the MLB culture for decades. I think Mickey Mantle admitted coming to the plate drunk. Jim Bouton exposed alot of drug use including the use of 'greenies' or speed. I know weekend warrior types and they said they did it as much for the post game drinking/hanging out as much as anything. I'm surprised this doesn't happen more often in baseball and other sports although because of the pace of baseball a player can probably get away with alot more.