When Brittney Griner is on the basketball court, everyone knows. At 6-foot-9, she towers over most other players. She snatches rebounds over her opponents’ outstretched arms, and her teammates know the surest way to score: Deliver the ball to her.

Since the Phoenix Mercury drafted Griner No. 1 overall in 2013, she has become one of the most dominant players ever: a seven-time All-Star, a W.N.B.A. champion and a two-time Olympian with matching gold medals.

But now Griner, 31, has become entangled in a geopolitical quandary. Instead of preparing for the W.N.B.A. season that’s less than two months away, she is believed to be detained in Russia on what customs officials described as drug charges, with little word on her case or her well-being during the war in Ukraine.

“With all the problems with Russia and them attacking Ukraine, has Brittney become a political bargaining chip?” said Debbie Jackson, Griner’s high school basketball coach. “Is this part of politics? So much of it doesn’t make any sense to me that I find it hard to believe that this is really the true thing that happened.”

Griner was in Russia playing for a professional basketball league, a common off-season practice for W.N.B.A. players, who can earn salaries in overseas leagues well beyond what their American teams pay. The date and circumstances of Griner’s potential detention were not known, and the W.N.B.A. said all of its players except for Griner were out of the country by Saturday.

Griner is said to be facing up to 10 years in prison if convicted on the drug charges, based on accusations that she had vape cartridges containing hashish oil in her luggage. The Russian authorities, who said Saturday that they had detained an American athlete on these drug charges, did not name Griner, but the Russian news agency Tass did.

On Monday, Jen Psaki, the White House press secretary, said she had seen reports about Griner but that federal privacy law prevented the U.S. government from discussing a person’s detention without their written consent. American officials have repeatedly accused Russia of detaining U.S. citizens on pretexts.

Representatives for Griner have declined to comment on Griner’s status beyond a statement that they were working to get her back to the United States. The uncertainty has caused an outpouring among fans and supporters of Griner, a groundbreaking player known for her unmatched blitz of dunks and her standing as one of the most prominent gay athletes.

A congresswoman in Houston, Griner’s hometown, has demanded her release. W.N.B.A. players have posted “Free Brittney” messages on Twitter.

“There are no words to express this pain,” Brittney’s wife, Cherelle Griner, wrote on Monday in an Instagram post addressed to Brittney. “I’m hurting, we’re hurting. We await the day to love on you as a family.”

‘Nobody can do what she can do’

Griner was a 5-foot-8 freshman on the volleyball team at Nimitz High School in Houston when Jackson approached her about playing basketball.

Griner initially laughed at the thought of trying out for a sport she’d never played and knew little about. But she quickly fell in love with it, Jackson said. It helped that she grew nearly a foot, to 6 feet 7 inches tall, by her senior year.

“She wasn’t like a clumsy tall person that had to grow into her body,” Jackson said. “She was really quite gifted as far as coordination.”

Griner earned a basketball scholarship to Baylor University, where for four years she performed with a combination of size, skill, fluidity and speed unlike any other women’s basketball player in the country. She could score at will under the basket, and highlight-reel dunks made her mesmerizing.

“Nobody can do what she can do,” Nancy Lieberman, the first woman to play on a professional men’s team, said during Griner’s freshman season at Baylor. “Not Cheryl Miller. Not Lisa Leslie. Not Candace Parker.”

Griner led Baylor to an undefeated record during the 2011-12 season, which the Bears capped with a win over Notre Dame in the national championship game. She won the Big 12 Player of the Year Award three times and made 18 dunks at Baylor. Before her, few women had dunked in a college game at all.

‘She was absolutely a force’

The Mercury drafted Griner in 2013, in the hope that she would rejuvenate their franchise. The turnaround was swift with Griner playing alongside Diana Taurasi, the W.N.B.A.’s career scoring leader. The Mercury made the playoffs during Griner’s rookie season and won a championship in her second. Last season, she was key to the Mercury’s run to the W.N.B.A. finals, where they lost to the Chicago Sky.

“In terms of talent, she was absolutely a force and continues to be a force,” said Pamela Wheeler, a former head of the W.N.B.A. players’ union. “I think that everyone was looking for her to help guide the league, which she did, into a new era.”

The year Griner was drafted, the league rebranded, changing its logo and focusing on promoting three rookies: Griner, Skylar Diggins-Smith and Elena Delle Donne.

Griner seemed to be a good fit, with an engaging personality, a willingness to laugh at herself and a passion for calling out bullying. She was also open about being gay, which has become more common in sports, in part because of her.

“I’m up for the challenge,” Griner said at the time about being part of the rebranding. “I changed stuff in college basketball, I guess you could say, so I’m up for it. I never shy from anything. Whatever’s thrown at me, I’m ready for it.”

As she elevated her game domestically, Griner also made a name for herself in international basketball. She won two Olympic gold medals with the United States women’s national team, in 2016 and 2021, and started playing for teams in Russia and China during W.N.B.A. off-seasons.

‘For the money’ and ‘For the love of the game’

Nearly half of the W.N.B.A.’s 144 players were believed to be playing for international teams this off-season, including more than a dozen in Russia and Ukraine. Griner has played for the Russian team UMMC Ekaterinburg for several years.

“While a number of players are doing it for the money as well,” said Wheeler, the former union leader, “they’re also doing it for the love of the game and continuing to be able to play and continue to keep themselves in playing shape.”

The maximum base salary for W.N.B.A. players is about $228,000, but international teams have been known to pay several hundred thousand dollars, and even more than $1 million. Griner is set to earn just under the W.N.B.A. max in the 2022 season. With the W.N.B.A.’s minimum salary around $60,000, many players earn the bulk of their income by playing abroad.

But playing overseas is not a “tourist opportunity” for most players, said Dr. Courtney Cox, an assistant professor at the University of Oregon, who said she traveled to Russia in 2018 to do research for a book about women’s professional basketball around the world.

“There’s this whisper network of where is it safe to play, where players are sharing information: where you get paid on time, where they look out for you, the better trainers, all this information,” Cox said. “There’s kind of a trauma bond, I think, that happens, when you play in some of these spaces where you might be one of the only American players, depending on the policies of the league.”

After Russia invaded Ukraine on Feb. 24, W.N.B.A. players in both countries fled.

‘She pushes back on gender roles’

Playing in the United States can come with its own issues. In her memoir “In My Skin,” Griner wrote about her time at Baylor, a Baptist-­affiliated school that had an official policy against homosexuality at the time. In the book, Griner said that Kim Mulkey, her coach, had warned Griner to “keep your business behind closed doors” and told her to cover her tattoos and delete social media posts about her girlfriend and L.G.B.T. issues.

But the Griner who entered the W.N.B.A. displayed a determination to show that she was comfortable being herself. She talked about being gay, wore fitted suits and bow ties, showed off her tattoos and modeled men’s clothing for Nike as the first openly gay athlete endorsed by the brand.

“She framed herself as somebody who was just herself,” said Amira Rose Davis, an assistant professor at Penn State University who specializes in race, sports and gender. She added: “So, when she signs with Nike and when she pushes back on gender roles or when she’s doing the cover shoots, it’s elevating the power of athletes in the game to write their own narratives about themselves.”

In May 2015, Griner married Tulsa Shock forward Glory Johnson, just weeks after they were arrested after fighting at their house in Phoenix. The W.N.B.A. suspended each of them for seven games, and they soon ended their relationship.

In 2019, Brittney Griner married Cherelle, who also attended Baylor. In an Instagram post on Saturday, Cherelle thanked those who had shown support and asked for privacy “as we continue to work on getting my wife home safely.”

‘It’s just hard to believe’

Little has been said publicly about Griner’s situation in Russia. Griner’s agent, Lindsay Kagawa Colas, declined to provide details, including whether Griner had been detained.

Colas said in a statement that she was “aware of the situation” in Russia and had been in contact with Griner and her “legal representation” there. “As we work to get her home, her mental and physical health remain our primary concern,” Colas said.

Jackson, Griner’s former high school coach, doubts the charges.

“It’s just hard to believe that Brittney, or any professional athlete that knows the laws of that country and the cultural differences and norms and just the completely different political system, would even think about putting in their carry-on bag something that was a banned substance in that country,” she said.

Public demands by American officials for the release of Americans detained abroad typically have little effect on foreign captors. Such cases are frequently resolved through behind-the-scenes diplomacy, and the details may never become public. Some analysts said that elevating the case into the political arena with angry demands could make it more difficult to resolve and put pressure on the other country to not be seen as giving in without a clear win.

Griner’s family and friends just want her home. Johnson, her former wife, posted a message of support on Instagram.

Cherelle Griner said on Instagram that this was “one of the weakest moments of my life.”

“My heart, our hearts, are all skipping beats every day that goes by,” she said.

Lara Jakes and Michael Crowley contributed reporting.