Yeah I red the JDA pretty thoroughly yesterday, and there is language in there to suspend for possession or selling of PED's or other drugs as well. But they also provide actual suspension length numbers. The reason it's up to 162 games is under the Basic Agreement, where allegedly a-rod tried to obstruct their investigation.
Under the Basic Agreement ARTICLE XII—Discipline "B. Conduct Detrimental or Prejudicial to Baseball Players may be disciplined for just cause for conduct that is materially detrimental or materially prejudicial to the best interests of Baseball including, but not limited to, engaging in conduct in violation of federal, state or local law. The Commissioner and a Club shall not discipline a Player for the same act or conduct under this provision. In cases of this type, a Club may only discipline a Player, or take other adverse action against him, when the Commissioner defers the disciplinary decision to the Club."
I looked through pretty thoroughly though, and nowhere in the Basic agreement does is say how long or short suspensions could be if someone is suspended under this clause. It's incredibly broad, basically just means if the Commissioner thinks a player has done something bad, he can suspend them as long as the team has not taken any action.