Despite continuing legislative (and societal) acceptance, the 2011 Collective Bargaining Agreement—negotiated by the owners and the players—still tests players for marijuana and disciplines them for positive tests. Many fans (and media) erroneously compare and contrast penalties for marijuana use to those for things like deflated footballs or domestic violence. In the latter cases, the Commissioner has wide discretion; with marijuana use, it is collectively bargained. Indeed, the topic of marijuana use represents one of the only things the NFL and NFLPA have agreed on since the negotiation of the 2011 CBA.
The two sides agreed to a revision that raised the threshold required to test positive for marijuana from 15 nanograms of THC per milliliter to 35 nanograms (for comparison’s sake, Major League Baseball uses a threshold of 50 nanograms, and the World Anti-Doping Agency uses a threshold of 150 nanograms). The relaxation of the threshold for marijuana, such that it was, answered player concerns for invoking a positive test due to second-hand smoke. The NFL, however, did extract a concession for that, with a revised policy that now includes testing for HGH.
As to the logistics and timing of marijuana testing in the NFL, this has been much publicized: It is not a drug test; it is an intelligence test. Players who have not previously tested positive are only tested once a year, and only during a four-month offseason window that begins on April 20 (yes, 4/20, maybe the NFL and NFLPA do have a sense of humor) and August 9.