The Sabres provided the update Tuesday, a day after Cozens was scheduled to visit a specialist. Cozens will have the procedure Wednesday.
He was hurt Saturday during a three-on-three scrimmage on the final day of the Sabres' developmental camp. A video showed Cozens leaving the ice with his thumb appearing dislocated.
Afterward, the Canadian said he was confident his thumb wasn't broken.
The 18-year-old center was selected with the No. 7 pick in the draft last month.