Chandler played for the Mavericks last season.
ESPN's Marc Stein reports the deal is worth $52 million over four years.
Chandler, 32, started 75 games for the Mavericks last season, averaging 10.3 points and 11.5 rebounds in 30.5 minutes per game. The 14-year pro played his highest total of regular season games since the 2007-08 season, when he was with New Orleans.
Wojnarowski reports that the Suns will try to use Chandler as part of their pitch to Blazers free-agent forward LaMarcus Aldridge.
Earlier on Wednesday, Yahoo! Sports reported that Suns point guard Brandon Knight had agreed to a five-year, $70 million extension with the team.
The Suns finished 39-43 in 2014-15, missing the playoffs for the fifth consecutive season.
- Stanley Kay