Marijuana is fully legal in 10 states, which are home to eight NFL teams (25 percent of the league), including the Los Angeles Rams and New England Patriots

Half the players taking to the gridiron on Sunday with a shot to play in this year's Super Bowl spent the current season in places where marijuana is legal—and, legal or not, weed use is widespread in the National Football League for both recreational and medicinal reasons.

But as the social stigma and legal prohibition of marijuana use is fading across America, the NFL remains stubbornly committed to keeping the substance outlawed.

For now.

Last month, NBC Sports' Mike Florio reported that team owners are increasingly interested in legalizaing weed, though it remains unlikely that the league will adjust its current policy before 2021 when the owners and the players' union are scheduled to renegotiate the collective bargaining agreement.

"The NFL realizes that there's no longer any good reason to keep the best football players from playing football over marijuana," Florio wrote. "But the NFL isn't yet willing to make dramatic and wholesale changes to the marijuana testing policy because the NFL hopes to dangle the changes within the context of collective bargaining, securing a concession from the union in exchange for softening a policy that badly needs to be softened."

By then, America's most popular sport will have fallen even farther behind the country as a whole. When the Denver Broncos and the Seattle Seahawks played in the Super Bowl in February 2014, they were the only two teams in the league hailing from states where weed was legal—a super bowl, indeed. Just five years later, there are 10 states where recreational marijuana is legal, and those states are home to eight NFL franchises (25 percent of the league), including the Los Angeles Rams and New England Patriots, who will play in Sunday's conference title games.

While the NFL has never allowed players to use marijuana for any reason, there is a well-documented history of teams handing out pharmaceutical pain-killers by the handful. "The medicine being pumped into these guys is just killing people," former player Nate Jackson told Rolling Stone in 2016, as part of an excellent piece on the league's nonsensical marijuana rules and how they've led to an over-reliance on opioids.