An All-Star the last five years, Wall will miss his first game of the season. He is averaging 21.3 points and 8.4 assists.
The Hawks also will be without starter Taurean Prince for the next three weeks after the forward injured his left ankle in Monday's loss to Golden State.
Washington (10-14) has won two straight and four of six. Atlanta (5-19), riding a three-game losing streak, has the NBA's third-worst record.