I finally answered this question, however I really believe this is strictly a yes or no answer. I voted yes, because the player has to have some accountability for his actions/decisions. Yes, just a plant is way to vague for my tastes. I was once a pot head, but I now choose to abuse a different drug of choice. Whilst being a pot smoker, I was capable of going through the motions of day to day life, but it was too easy to just sit back, roll up a joint and smoke it and easily blame my actions on being wasted; pro athletes can not do what I did and perform at a high level.
One poster said that if the player smoked before the game, the pregame workout would make him ready and focused to play the game. I don't believe that to be the case.