Griner, the W.N.B.A. star detained in Russia on drug charges, is one of many athletes who have said cannabis helps with sports injuries. But it is banned by sports leagues and illegal in many places.Shawn Kemp played most of his N.B.A. career before the league began testing players for marijuana use in 1999. So after playing in the bruising, physical games typical of the N.B.A. in the 1990s, he would smoke. He didn’t like taking pain-relief pills.“I was able to go home and smoke pot, and it was able to benefit my body, calm my body down,” said Kemp, who is 6-foot-10 and was upward of 230 pounds during his 14-year career of highlight-reel dunks, mostly with the Seattle SuperSonics. He said the drug seemed to help with inflammation in his knees and other joints.Now Kemp, 52, owns a stake in a Seattle marijuana dispensary bearing his name.In the two decades since the N.B.A. and its players’ union agreed to begin testing for marijuana, or cannabis, the drug’s perception has undergone a makeover in the United States, where it has been illegal for decades. Researchers don’t fully understand its possible medical benefits or harmful effects, but it has become legal in many states and some professional sports leagues are reconsidering punitive policies around its use. Many athletes say they use cannabis for pain management.Brittney Griner is one of them.Griner, a W.N.B.A. star, was detained in Russia in February after customs officials said they found vape cartridges with hashish oil, a cannabis derivative, in her luggage. Cannabis is illegal in Russia, and Griner, 31, faces a 10-year sentence in a Russian penal colony on drug trafficking charges if she is formally convicted. She has pleaded guilty, but testified that she did not intend to pack the cartridges. Her legal team said she was authorized to use medicinal cannabis in Arizona, where she has played for the Phoenix Mercury since 2013.Griner’s case has drawn attention to the debate over marijuana use for recreation and relief. The U.S. State Department said it considered Griner to be “wrongfully detained” and would work for her release no matter how the trial ended. But in the United States, thousands of people are in prison for using or selling marijuana, and it remains illegal at the federal level even as dozens of states have legalized it for medicinal use or recreational use. It is banned in the W.N.B.A.Kemp and many others are urging sports leagues and lawmakers to change.Shawn Kemp at the grand opening of his cannabis shop in Seattle in 2020. He said his 14-year N.B.A. career might have been longer had he been able to use marijuana without penalty in his final years.Ted S. Warren/Associated Press“There’s still a lot for people to learn throughout the world with this stuff,” Kemp said. “And hopefully they will someday, where people will see cannabis oil and all these things and realize some athletes use this stuff to benefit their body, calm their body down from beating up their body so much on a daily basis.”Kemp said he was deeply saddened when he heard about Griner’s detention.“I’m such a fan of hers, to see her with that big, tall body to be able to move the way she does. She’s changed the game of the W.N.B.A.,” he said.In testimony at her trial, Griner described injuries to her spine, ankle and knees, some of which required her to use a wheelchair for months, according to Reuters. Like Kemp, the 6-foot-9 Griner has endured bumping and banging as she battled for rebounds and dunks. Many athletes believe marijuana is healthier for dealing with pain and anxiety than the addictive opioids and other medications historically prescribed by doctors.Eugene Monroe, a former N.F.L. player who has invested in cannabis companies, said he began using cannabis for pain relief after he realized other types of medications were not working for him.“Going into the building every day, getting Vicodin, anti-inflammatories — there was something about that, over time, that made me think: ‘Am I even needing these pills? Is this an addiction causing me to come in here and see the team doctor?’” Monroe said.The N.F.L. relaxed its marijuana policy in 2020 to allow for limited use, but it can still fine and suspend players for exceeding the limits. In the basketball leagues, only repeated offenses lead to a suspension. Griner will not face punishment from the W.N.B.A. if she returns to the league, an official who was not authorized to speak on the record because of the sensitivity of the matter told The New York Times.The N.B.A. halted testing when the coronavirus pandemic began, saying it was focusing on performance-enhancing drugs instead. Major League Baseball removed marijuana from its list of banned substances in 2019, but players can still be disciplined for being under the influence during team activities or breaking the law to use it (as, for example, they could be for driving under the influence of alcohol). The N.H.L. tests for marijuana, but does not penalize players for a positive result.Calvin Johnson, right, the former Detroit Lions star, with Rob Sims, his partner in a cannabis business, in June 2021. Johnson and Sims looked at marijuana plants for their business.Carlos Osorio/Associated PressLast year, Kevin Durant, the All-Star forward for the N.B.A.’s Nets, announced a partnership with the tech company Weedmaps, which helps users find marijuana dispensaries. “I think it’s far past time to address the stigmas around cannabis that still exist in the sports world as well as globally,” Durant told ESPN, which said he declined to discuss whether he used marijuana.Al Harrington, a retired N.B.A. player who has invested in cannabis companies, told GQ last year that he thought 85 percent of N.B.A. players used “some type of cannabis.”The W.N.B.A.’s Sue Bird has endorsed a cannabis products brand aimed at athletes. Lauren Jackson, a women’s basketball great, credited medicinal cannabis for her long-awaited return to the court this year after dealing with chronic knee pain. She is listed on the advisory board of an Australian company that sells cannabis products. Many former N.B.A. and N.F.L. players, like the retired Detroit Lions star Calvin Johnson, have invested in cannabis companies.About a month before Griner’s detention became public, the N.F.L. announced it had granted $1 million in total to the University of California, San Diego, and Canada’s University of Regina to study the effects of cannabinoids — the compounds in cannabis — on pain management. U.C. San Diego’s research will involve professional rugby players.Until recently, cannabis research has typically focused on abuse and whether it enhances performance in sports, rather than any potential benefits.In 2017, the National Academies of Sciences, Engineering, and Medicine said a review of research since 1999 had shown “substantial evidence that cannabis is an effective treatment for chronic pain in adults.” But its review also found indications that cannabis use can hinder learning, memory and attention and that its regular use likely increases the risk of developing social anxiety disorders. There was also moderate evidence that regularly smoking marijuana could cause respiratory problems.Another review published in the Clinical Journal of Sport Medicine in 2018 found that early cannabis research showed a decrease in athletic performance. It also said there was little research examining cannabis use in elite athletes.Kevin Boehnke, a researcher at the University of Michigan’s Chronic Pain and Fatigue Research Center, said “cannabis tends to be safer” than anti-inflammatories and opioids that are often used for chronic pain.“That doesn’t mean it’s without risk,” he said, but added that the goal should be to use treatments that are the “lowest risk and most acceptable to the person who’s using it.”“At this point there’s not really a good justification from at least a pain management standpoint of why that should not be an available tool,” he said.Dr. David R. McDuff, the director of the sports psychiatry program at the University of Maryland, said many substance abuse referrals early in his career involved athletes who were binge-drinking alcohol. Later, he saw a shift to patients who were using cannabis.“If you look at the universe of people that use cannabis, about 10 percent of those will develop a cannabis use disorder,” said Dr. McDuff, who specializes in addiction and trauma. “They can be very serious. They usually will start by reducing motivation and initiative.”He said he was particularly concerned about how cannabis could affect adolescents’ brain development.Despite his caution, Dr. McDuff said he believes cannabis has medicinal properties that should be better studied. He said one barrier to that happening in the United States is marijuana’s federal classification as a Schedule I drug, meaning it is said to have no medical use and is likely to be abused. It is in the same category as drugs like heroin and ecstasy.Griner said she used cannabis products to manage pain from basketball injuries.Ethan Miller/Getty ImagesDennis Jensen, a researcher at McGill University in Montreal, said Canada’s 2018 marijuana legalization opened the door for more research there.“There’s a lot of anecdotes, there’s a lot of individual athlete reports, but the research does not necessarily support or refute anything that they’re saying as of yet,” he said.Riley Cote, a former member of the N.H.L.’s Philadelphia Flyers, said he tried marijuana as a youth player and found that it relieved his pain from fighting during games, even though he didn’t understand why. He co-founded Athletes for CARE, a nonprofit that promotes education and research for using cannabis and hemp as therapeutic alternatives. It receives some funding from cannabis product and branding companies.Anna Symonds, a professional rugby player and a member of Athletes for CARE, said she was heartbroken and frustrated when she learned why Griner had been detained. “It’s ridiculous that cannabis is criminalized, and that causes many more problems than it ever could solve,” she said.Symonds said she tried painkillers and muscle relaxants to ease the pain from muscle spasms and herniated and bulging discs in her back. Nothing, she said, worked like cannabis.Ricky Williams, a former N.F.L. player, said he hoped Griner’s situation would cause people to think about those imprisoned in the United States for cannabis-related offenses. Williams started a cannabis brand last year.He won the Heisman Trophy in 1998, but had a halting N.F.L. career in part because of discipline from the league related to his marijuana use.Ricky Williams, who played 11 seasons in the N.F.L., said using marijuana helped him realize he did not want to play football anymore.Photo By Eliot J. Schechter/Getty Images“I value feeling good, and I’m comfortable pushing the boundary of the rules, so I kept on going with it,” Williams said. “For me it became an issue because what I did for a living conflicted with my choice to consume cannabis.”Using marijuana helped him realize that playing football was not what he wanted to do for a living, he said.“I use cannabis now to accentuate what I do, not to deal with my life,” Williams said.While he believes cannabis helps with pain, he wishes its use was more widely accepted even for those without chronic pain.“I look forward to the day when the N.F.L. says, ‘This seems to really help our players, they really want it and we haven’t found any reason to not do it so let’s support it,’” Williams said. He added: “At least ask, have that conversation instead of just assuming that they’re doing something bad, and then punishing them. That was what happened to me and it doesn’t make any sense.”For Kemp, whose N.B.A. career ended in 2003, the changing mood about marijuana use among athletes like Griner is welcome, if perhaps too late for him. “I would have kept playing basketball if I could have used marijuana products back when I retired,” he said.He and his wife usually go out to see Griner’s Mercury play the Seattle Storm each summer. The teams’ matchups have come and gone this season, without the detained Griner, but she’s still on Kemp’s mind. “Hopefully she can get home with a safe return,” he said. “I miss seeing her play.” More