The Connecticut Sun are finalizing a sign-and-trade to acquire star forward Alyssa Thomas from the Phoenix Mercury, ESPN's Alexa Philippou reported Tuesday.

Philippou reported the full return for the Sun, including the No. 12 pick in the draft:

The transaction cannot be finalized until Feb. 1, per Philippou.

The Sun had exclusive negotiating rights with Thomas after tagging her with a core designation to stop her hitting unrestricted free agency this offseason.

Thomas, who has finished the last three seasons as an All-Star and MVP finalist, is a two-time Defensive Player of the Year runner-up. She helped the Sun reach the WNBA Finals in 2019 and 2022.

The five-time All-Star expressed dissatisfaction with the Sun during the 2024 postseason. The team prepared for their first-round matchup with Caitlin Clark and the Indiana Fever on a half-court shared with a community center event, a setup Thomas described to The Next Hoops' Noa Dalzell as "the ultimate disrespect."

"It's normal at this point. I mean, Mohegan has to do better," Thomas told Dalzell. "We're [a] professional team. We're competing for playoffs... We need more, we need better to compete at the highest level."

That wasn't the only time Thomas has appeared unhappy with the standards set by the Sun organization. She said after winning a gold medal at the 2024 Paris Olympics with Team USA that the experience had showed her the Sun were "super behind" in terms of practice facilities (h/t NBC Sports Boston's Justin Leger.)

The Mercury, meanwhile, opened a $100 million practice facility ahead of the 2024 WNBA season. Access to those facilities might have encouraged Thomas, who had to acquiesce to any potential sign-and-trade, to agree to the move to Phoenix.

Thomas heading to Mercury could help convince her partner and former Sun teammate DeWanna Bonner to sign in Phoenix as well. Bonner hit unrestricted free agency after the 2024 season.

The departure of Thomas and the potential exit of Bonner mark the end of an era for the Sun, who have reached the semifinal in five straight seasons with the duo on the team.

The Mercury roster is also in flux with Brittney Griner hitting free agency and Diana Taurasi potentially retiring. Should Griner and Taurasi both leave, the Mercury could theoretically build around a new core of Thomas and potentially Bonner.

Natasha Cloud will at least bring loads of experience to the roster as a nine-year veteran who won the 2019 title with the Washington Mystics. She has also been named to the All-Defensive team three times in her career.

Rebecca Allen could also provide depth after averaging 7.4 points per game last season.

The news marks the second blockbuster WNBA trade reported by Philippou this week, following the news of a three-team trade that sent Jewell Loyd to the Las Vegas Aces and Kelsey Plum to the Los Angeles Sparks.