The No. 26 overall pick in in the 2019 draft, Windler had yet to play for Cleveland after sustaining a stress reaction in his lower left leg during workouts prior to training camp. He played for the Canton Charge in December but began experiencing symptoms and was shut down.
"After an extended period of rehabilitation and treatment over the last several months, it was determined the injury will now require surgery," the Cavaliers said in a statement on Monday. "A timetable for his return to basketball activities will be established post-surgery, which is scheduled for January 21."