The team announced the signing Tuesday.

Griner, a free agent who was detained last February and imprisoned for 10 months in Russia on drug possession charges while traveling overseas, had indicated in December in a social media post that she planned to return this season. She returned to the United States in December in a high-profile prisoner exchange.

“We missed BG every day that she was gone and, while basketball was not our primary concern, her presence on the floor, in our locker room, around our organization, and within our community was greatly missed,“ Mercury general manager Jim Pitman said in a statement released by the team. “We will continue to use the resources of our organization to support her, on and off the floor, and we are thrilled for her that she gets to return to basketball, which she loves so dearly. This is a special signing and today is a special day for all of us.”

Griner, 32, led the Mercury to the 2021 WNBA Finals. The 6-foot-9 center, the No. 1 overall draft choice by Phoenix in 2013 out of Baylor, averaged 20.5 points and 9.5 rebounds that season.

“I do not think any of us will forget where we were on Dec. 8 when we heard BG was coming home or on Dec. 15 when she announced she intended not only to play basketball in 2023 but that it would be for the Mercury,” Mercury president of business operations Vince Kozar said in a statement. “And I know none of us will ever forget what it will feel like to welcome her back onto her home floor on May 21. To know BG is to love and appreciate BG, and we can’t wait to show her that in person with thousands and thousands of her biggest supporters exactly three months from today at our Welcome Home Opener.”

The longtime U.S. national team member did not participate in a training camp earlier this month, although USA Basketball has said she is welcome to rejoin the team when ready.

The Associated Press contributed to this report.