Defenseman Radim Mrtka on Saturday was among four prospects the Buffalo Sabres assigned to the Rochester Americans.
They also sent center Noah Ostlund and defensemen Vsevolod Komarov and Zachary Metsa to their AHL affiliate.
The Sabres, who open the season Thursday, must finalize their 23-man roster by Monday. They have 28 players left on their training camp roster.
Mrtka, the ninth overall pick this year, enjoyed a strong preseason, compiling one goal and two points in four games.
The Czech, 18, spent most of last season with the junior Seattle Thunderbirds after beginning the year playing pro hockey at home.
Most Canadian Hockey League players can’t play regularly in the AHL until they’re 20. Mrtka, however, was loaned to Seattle, making him eligible.