"Thank you, mom and dad, for everything you have done for me on and off the court," Sengun, 18, said on Twitter.
"I could not have had two better parents and you always pushed me to be my best. Thank you to all the coaches and players who made me better every day-it has been a very special year."
He added: "Looking forward to finishing strong in Turkey and then embarking on the next challenge of playing in the best league in the world."
Sengun has played professionally in Turkey since 2018.
Now a key player for Istanbul's Besiktas, during the 2020-21 season Sengun has averaged 19.2 points, 9.4 rebounds, and 2.5 assists in 29 games.