The NFL has issued a warning to Cleveland Browns star Josh Gordon, ahead of a hearing that could see him suspended for the entire 2014 season.
Gordon failed a drugs test for the second time in his career in May, but the wide receiver recently claimed that secondhand smoke was to blame.
However, the league does not seem to be interested in his excuses, and has stated that he has a responsibility to look after his body.
Greg Aiello, NFL senior vice president of communications, said: "A cornerstone of both of our drug testing programs has always been that you are responsible for what is in your body.
"It is stated that way in the policies."
A year ago, Gordon claimed that he tested positive for codeine via some prescribed cough medicine, leading to a four-game ban which was eventually reduced to two.
With this being a second offence, he is expected to be punished much more heavily.
Recent reports suggested that Gordon has lost the trust of his teammates ahead of his hearing on Friday.