The Al Horford experiment lasted exactly one season in Philadelphia.
As part of the deal, Philadelphia will also be sending the 34th pick in Wednesday night's NBA draft, a lightly protected 2025 first-round pick and the draft rights to Serbian guard Vasilije Micic to Oklahoma City.
The Thunder will be sending guard Terrance Ferguson to the Sixers along with Green.
Horford, 34, signed a four-year, $109 million contract with Philadelphia as a free agent last summer, as the Sixers hoped the combination of prying him away from their blood rivals, the Boston Celtics, as well as pairing him with Joel Embiid -- whom he'd always been effective guarding as a member of the Celtics -- would pay dividends. Instead, the fit between the two was clunky from the start and never improved, to the point where Horford was removed from the starting lineup for the first time in his career in favor of second-year guard Shake Milton.
"I'd like to say, I haven't been here, but Al Horford is a really good player," Morey said late Wednesday night after Philadelphia completed its draft. "I know there's been some buzz around fit and things like that, but honestly, we tried to sign him at my past team, and I don't like how that went down here because he's very good."
This trade also delivers significant financial savings for the Sixers -- more than $25 million in combined payroll and luxury taxes, per ESPN's Bobby Marks.
This is the first move that new president of basketball operations Daryl Morey has made since arriving in Philadelphia this month after a 13-year stint in charge of the Houston Rockets.
Green, 33, has now been traded twice in a week. He was part of the deal, finalized Wednesday night, that sent guard Dennis Schroder from Oklahoma City to Los Angeles.
A three-time champion, including the past two seasons with the Toronto Raptors and the Lakers, Green, a career 40% 3-point shooter, will provide two things Philadelphia desperately needed: a better positional fit than Horford and shooting to put around stars Ben Simmons and Embiid.
Ferguson, 22, was a first-round pick by the Thunder in 2017, and he gives the Sixers another athletic defender on the wing.
Micic, 26, was a second-round pick by the Sixers in 2014 and plays for Anadolu Efes in the Turkish Super League, one of the top teams in Europe. He was a second-team All-EuroLeague selection in 2019.
The first-round pick that Oklahoma City receives, meanwhile, only adds to the massive war chest of first-rounders Thunder general manager Sam Presti has accumulated -- a remarkable 17 selections through the 2026 NBA draft, including the 25th and 28th picks in this year's draft.
The Thunder have now made three trades in the past week -- all of which brought a first-round pick back to the franchise.
In addition to both deals involving Green, the Thunder traded future Hall of Famer Chris Paul and Abdel Nader to the Phoenix Suns for Ricky Rubio, Kelly Oubre Jr., Ty Jerome, Jalen Lecque and a 2022 first-round pick earlier this week.
Later Wednesday, the Minnesota Timberwolves reached an agreement with Oklahoma City to trade their 17th draft pick, Serbian forward Aleksej Pokusevski, for Rubio and the 25th and 28th picks, sources told ESPN.
Rubio, the slick-passing ball handler, played for Minnesota in his first six seasons in the league and is beloved by the fan base despite a rash of injuries that minimized his impact.
The Associated Press contributed to this report.