Former Heisman Trophy winner Ricky Williams has become an ardent medical marijuana advocate, speaking at conferences and even releasing a documentary with Sports Illustrated that spotlighted how marijuana has helped him treat the lingering symptoms of old injuries. Now he's opening up about why he thinks the NFL still bans marijuana - which is arguably a safer and more effective alternative to opioid painkillers used (and often abused) by athletes.

Williams told Bill Simmons on last night's episode of Any Given Wednesday that players and agents as well as team owners are to blame for the league's cannabis ban.

"I think a lot of the time the NFL gets the blame. But it's something that's negotiated in the collective bargaining agreement. I think what it comes down to is the players say we'd rather have more money. And I think the owners use the drug policy as leverage for us to give up other things."

However, owners have other reasons to support marijuana prohibition in the league. Williams said they also support the ban because they're invested in how the public perceives the league. "It's more about protecting the NFL's image than anything else."

But that concern has overshadowed not only the safety but the success of players, according to Williams, who says that he would have been a hall-of-fame player had his career not been derailed by scandals and controversy surrounding his cannabis use. Those distractions, he argues, got in the way of realizing his potential as a player.