The 6-foot-5, 210-pound junior averaged 18.2 points and 8.9 rebounds this past season for the Owls.
"It just feels right to go back where it all started and I trust the coaching staff in Florida," said Koulechov, who was born in Russia but played his high school ball in Florida. "I wanna thank everyone who recruited me, especially Oklahoma, Lon Kruger and Carlin Hartman. They're truly exceptional people. I would be very lucky to play for them."