The Celtics and Hawks both will be missing big men when they square off Wednesday night at TD Garden. Boston downgraded starting center Neemias Queta from doubtful to out Wednesday afternoon. Teammate Jaylen Brown called his performance against Portland “exceptional.”The Hawks ruled out former Celtics center Kristaps Porzingis, who will miss his 10th straight game with Achilles tendonitis. Porzingis’ injury also sidelined him for the Celtics’ 132-106 win at Atlanta on Jan. 17. Atlanta also ruled out forward Zaccharie Risacher (knee) for Wednesday’s matchup, which tips off at 7:30 p.m.