Griner, a 32-year-old free agent, signed a one-year, $165,100 contract with the Mercury on Saturday, a source confirmed to ESPN. She'll return to the team that drafted her first overall in 2013 for a 10th season.
The last time Griner suited up for the Mercury was in 2021, when she led them on an unexpected run to the WNBA Finals, which Phoenix lost to the Chicago Sky. She missed the 2022 WNBA season while in detention in Russia.
Griner had one of the best years of her career in 2021, averaging 20.5 points, 1.9 blocks, 2.7 assists, and career-highs with 9.5 rebounds per game, 2.4 offensive rebounds and a .846 free throw percentage.
Griner, who also played pro basketball in Russia, was arrested at Moscow's Sheremetyevo Airport in February 2022 after Russian authorities said she was carrying vape canisters with cannabis oil. The U.S. State Department had declared Griner to be "wrongfully detained."
After months of strained negotiations, and an extraordinarily rare public revelation by the President Joe Biden's administration that it had made a "substantial proposal'' to get home Griner and another detained American, Paul Whelan, Griner's case resolved on Dec. 8 with a prisoner swap in which the WNBA star was exchanged in the United Arab Emirates for Russian arms dealer Viktor Bout.
Griner wrote in an Instagram post on Dec. 16 that she intended to play for the Mercury this season.
The Mercury open the season on the road against the Los Angeles Sparks on May 19. The team's first home game is two days later against the Chicago Sky.
News of Griner's deal with Phoenix was first reported by Her Hoop Stats.