The player, convicted by a Russian court in a controversial "drug trafficking" case, found herself despite herself plunged into the geopolitical crisis between Washington and Moscow, in the midst of the conflict in Ukraine.
US President Joe Biden has called the conviction of the 31-year-old double Olympic champion "unacceptable", the United States accusing Moscow of instrumentalizing her case to extract concessions from Washington.
The American administration has claimed for several days to have submitted to the Kremlin a proposal to obtain the release of Ms. Griner, but Russian diplomacy repeated that an exchange could only be discussed once the verdict has been passed.
"We are ready to discuss this subject, but only within the framework of the (diplomatic) channel that was agreed upon by Presidents (Vladimir) Putin and Biden," Russian Foreign Minister Sergei Lavrov said on Friday. a trip to Cambodia.
The Kremlin spokesman, Dmitri Peskov, specified that this specific channel of communication to negotiate the exchanges of prisoners had been the subject of an agreement between MM. Biden and Putin during talks in Geneva last year.
The head of the American diplomacy Antony Blinken, who had already had talks last week with Mr. Lavrov about an exchange, indicated Friday that the United States would "continue" to discuss it with Russia.
He also said Griner's conviction illustrated "the Russian government's use of illegitimate detentions to advance its interests by using individuals as political pawns."
- "Substantial and serious" offer -
Brittney Griner, considered one of the best basketball players in the world, was sentenced Thursday to nine years in prison for drug trafficking by a court in Khimki, near Moscow.
This heavy prison sentence raised a wave of indignation, especially in the world of sport.
She had been arrested in February at a Moscow airport with cannabis-based vaping liquid. She admitted having been in possession of this substance, however claiming to have brought it to Russia inadvertently and to use it legally in the United States as a painkiller.
She had come to Russia to play during the American offseason, a common practice for WNBA basketball players who often earn more money abroad than in the United States.
The sportswoman is one of several American citizens currently detained in Russia and whose release Washington wants.
Washington said last week it had made a "substantial" and "serious" offer to secure the return of Ms Griner and Paul Whelan, an American who is serving a 16-year prison sentence in Russia for "espionage".
- Russian arms dealer -
According to several American media, it would be a question of exchanging a famous Russian arms trafficker detained in the United States, Viktor Bout, against Brittney Griner and Paul Whelan.
Mr. Bout, arrested in Thailand in 2008 and serving a 25-year prison sentence in the United States, is nicknamed the "merchant of death". His extraordinary career was one of the inspirations for the film "Lord of War" in which Nicolas Cage plays a cynical arms dealer.
The arms dealer's wife, Alla Bout, also said Thursday that she hoped for an exchange, expressing her "compassion" towards those close to Brittney Griner. "May God ensure that our countries find an agreement," Ms. Bout told the Ria-Novosti news agency.
Neither Russia nor the United States have confirmed, and Moscow insists on its desire to keep the negotiations confidential, annoyed by statements made by American officials.
"If the Americans still decide to engage in public diplomacy and make resounding declarations (...) it is their business, and even their problem", said Friday Mr. Lavrov, estimating that Washington "cannot arrive not" to work "calmly and professionally" on many subjects.