According to the report, which cited a source, the free agent signed the deal on Saturday to return to the only WNBA team she has played for since they selected her with the first pick in the 2013 draft.

The Mercury, who open their 2023 WNBA season on May 19th at the Los Angeles Sparks, did not immediately respond when asked by Reuters to confirm the ESPN report.

Griner, a two-time Olympic gold medallist and eight-time Women's National Basketball Association All-Star, was arrested in February 2022 at an airport outside Moscow for carrying vape cartridges containing hashish oil in her luggage.

She was subsequently convicted of drug smuggling and later transferred to one of Russia's most notorious penal colonies, where former inmates have described torture, harsh beatings and slave labour conditions.

Griner was released last December in a prisoner swap with Russia in exchange for arms dealer Viktor Bout, a deal that was arranged after months of talks during a time of high tension between the two countries after Russia's February invasion of Ukraine.

In her first public statement since her release, Griner said last December that she would advocate for Americans detained abroad and that she planned to return to her WNBA team.

"I intend to play basketball for the WNBA's Phoenix Mercury this season, and in doing so, I look forward to being able to say 'thank you' to those of you who advocated, wrote, and posted for me in person soon," Griner wrote.

Griner last played for the Mercury in the 2021 WNBA season when she had one of the best years of her career and averaged 20.5 points, 9.5 rebounds and 2.7 assists over 30 games.