The Celtics roster is close to being filled with 14 of the 15 spots already taken. In addition to the 15 regular roster spots, NBA teams are also allowed two two-way spots for players who alternate time between the parent team and the G-League affiliate.
Boston had two such 2-way players, Jabari Bird and Kadeem Allen with the team last season. Both are participating in the Las Vegas Summer League, and it appears the Celtics are about to release Allen to create a 2-way spot for another player. Bird is currently a restricted free agent after receiving a qualifying offer from Boston.