Kemba Walker plans to be in Boston on Sunday to finalize a formal agreement for a four-year, $141 million deal with the Celtics, league sources told ESPN's Adrian Wojnarowski on Saturday.

The Celtics have targeted Walker, 29, as the No. 1 priority in free agency and an elite replacement for the departing Kyrie Irving, sources said.

NBA free agents can begin negotiating agreements with teams at 6 p.m. ET Sunday. Contracts can be officially signed July 6.

Walker is coming off his best season as a pro during his eight seasons with the Charlotte Hornets, averaging 25.6 points while playing in all 82 regular-season games.

After a season of locker room turmoil often centered around Irving's discontent, the Celtics crave the stability and leadership that Walker will provide -- along with being an All-Star talent in the prime of his career.

Boston can renounce the rights to restricted free agent Terry Rozier to clear the space to start Walker on a four-year deal beginning at $32 million annually.

Walker can plug into a Celtics lineup that includes Jayson Tatum, Gordon Hayward and Jaylen Brown. Boston can still pursue a center with its $4.8 million exception and deliver at the start of the season a team that could be competitive in the Eastern Conference.

Charlotte, meanwhile, has declined to exercise its qualifying offer on Frank Kaminsky, allowing him to become an unrestricted free agent amid significant interest, a league source told ESPN.

The Hornets have been scouring the free-agent point guard market, considering such options as Elfrid Payton, T.J. McConnell, Ish Smith and Emmanuel Mudiay, league sources told ESPN.

Walker won a national championship at UConn in 2011 and is a New York City native.