It appears Humphries already has an agreement in place, per Marc J. Spears of Yahoo Sports:
The 31-year-old forward came to Phoenix in a Feb. 18 trade with the Washington Wizards. In his first game with the Suns, Humphries had a double-double with 18 points and 12 rebounds, and he averaged 7.3 points and 8.0 rebounds in four games.
According to Paul Coro of the Arizona Republic, the buyout was good timing for Humphries, who needs to join Atlanta before Tuesday in order to be eligible for a playoff roster. The 32-27 Hawks are currently the No. 5 seed in the Eastern Conference.
Humphries had the postseason on his mind all along, per Coro.
"Basketball always comes down to winning and competing, especially now that the season is so long," Humphries said. "(Joining a playoff team) is always an option."
Although Humphries was starting in Phoenix, it remains to be seen how he will fit in with Atlanta. After 12 seasons, he has shown he is not much of a scorer, averaging just 6.9 points per game.
However, his per-36-minute average of 11.0 rebounds shows he can be a solid body underneath and provide some depth for a Hawks team looking to make a playoff run.
All stats courtesy of Basketball-Reference.com.