For a player who was not even on the roster for the Sin City Celtics, big man Charles Bassey had an impressive impact.

LAS VEGAS — The Celtics released their Summer League roster on Tuesday but made one major addition before Friday’s opener against the Grizzlies. Boston brought aboard free agent center Charles Bassey to the roster in a surprise move, as the big man joined Amari Williams and Kenneth Lofton Jr. as the team’s primary bigs in Las Vegas.