As U.S. Embraces Marijuana, Sports May Need To Follow Suit For an advocacy group seeking attention, tying its cause to the kickoff of the NFL season is never a bad strategy. Such was the thinking behind a billboard unveiled Wednesday by the Marijuana Policy Project not far from Sports Authority Field at Mile High Stadium - home of the Broncos, who hosted the Baltimore Ravens Thursday night in the first game of the 2013 NFL campaign. "Stop Driving Players To Drink!" the 48 X 14 foot message says. A Safer Choice Is Now Legal (Here). The visual: a football next to a beer mug. Why didn't the Marijuana Policy Project post an actual joint on the billboard? "We want people to take a look at the billboard ad and ask themselves about why we treat alcohol differently from marijuana," says Mason Tvert, communications director for the Marijuana Policy Project. With the marijuana leaf, there tends to be this knee-jerk reaction of not liking it. Recreational marijuana is now legal (for those over 21) in Colorado and Washington, home to the Broncos and Seattle Seahawks. But the NFL and other sports leagues won't be allowing players to smoke up in those states. Drug policies are collectively bargained between leagues and players, and in the NFL, marijuana is prohibited. Under labor law, the NFL can punish players for doing something legal - as long as the players have agreed to the policy, which in this case, they have. MORE: Viewpoint - How Marijuana Decision Could Signal Turning Point In The U.S. War on Drugs Yet as the billboard implies, NFL players have had their share of trouble with alcohol, which the league doesn't prohibit. Since June 2012, 22 NFL players have been arrested on DUI-related charges, according to a database of arrests by UT-San Diego. In December Josh Brent, a Dallas Cowboys defensive tackle, was allegedly driving drunk when his vehicle crashed, killing his passenger and teammate Jerry Brown. Brent has been indicted for intoxication manslaughter. In July, two Denver front office execs were arrested for drunk driving. On Wednesday, the NFL Players Association announced a deal with a deal with Uber, the ride-sharing app, that may help prevent these sorts of incidents. "Beginning this month, NFL players will be able to summon a ride in any of Uber's international locations, including nearly 20 U.S. NFL team cities and Pro Bowl host Honolulu," the players association explained in a statement. Once a ride is requested via Uber's smartphone app, the software will display the car's location on a map and an Uber will arrive within minutes .... Uber and the NFLPA will distribute personalized keychain cards containing ride credits [note: worth $200] to every active NFL player. The partnership will also provide players with new rider gift cards for friends and family to promote responsibility to those closest to them. In a way, this deal speaks to the billboard's point. The union is acknowledging the dangers of alcohol. So why are players subject to suspension if they stay home and smoke up? The World Anti-Doping Agency has classified marijuana as a performance-enhancing drug, in part for its ability to ease anxiety. This classification has been panned by some scientists. David Nutt, a professor of neuropsychopharmacology at Imperial College London told Reuters back in 2012: "There's no evidence cannabis is ever performance enhancing in sport, and since its use is legal in a number of countries, there's no reason for it to be banned by WADA." In the NFL, however, marijuana is covered under the substance abuse policy, rather than the performance-enhancing drug policy. "Hard to believe it would be performance enhancing in any sport associated with speed, timing, power, focus or endurance," writes Dr. Michael Joyner, an anesthesiologist and doping expert at the Mayo Clinic, in an email. Banning marijuana can save sports leagues like the NFL public relations headaches. Americans are comfortable seeing their athletes sipping beer. Smoking marijuana is another story. But drug policies can evolve. In May, the World Anti-Doping Agency raised the threshold for a positive test by a factor of ten, from 15 ng/mL (nanograms per millilter) to 150 ng/mL. The Ultimate Fighting Championship followed suit, raising its threshold from 50 ng/mL to 150 ng/mL. Last week U.S. Attorney General Eric Holder said that federal prosecutors won't pursue casual marijuana users in Colorado and Washington, as long as they're obeying the state laws. As the pro-marijuana movement gains momentum in the U.S., the drug policies in sports may shift with it. MORE: Man Arrested For Allegedly Firing Marijuana At Jail Via Bow and Arrow