Yahoo Sports first reported the deal.
Len averaged 8.5 points and 7.5 rebounds per game for the Suns last season. The 25-year-old was taken fifth overall by Phoenix in the 2013 draft. He's averaged 7.2 points and 6.5 rebounds in his career.
The Hawks are going to acquire the $27.9 million expiring contract of Carmelo Anthony and then waive him, sources told ESPN last week. The Thunder will also send a 2022 protected first-round pick to the Hawks for guard Dennis Schroder and forward Mike Muscala. The Thunder will then send Muscala to the 76ers for forward Timothe Luwawu-Cabarrot, and Philadelphia will send guard Justin Anderson to Atlanta, league sources said.
The Len contract is expected to be finalized after the trade is completed.