The team made the announcement shortly before tipoff, before going on to a 110-88 win.
Lou Williams started in place of Young, scoring 21 points to go with eight assists.
Hawks coach Nate McMillan said afterward that Young didn't feel comfortable putting pressure on his foot before Tuesday's game, and that he's likely to be a game-time decision again for Thursday's Game 5.
With 36 seconds remaining in the third quarter of Game 3 on Sunday, Young inadvertently stepped on the right foot of referee Sean Wright. Young went back to the locker room briefly before returning to the game with just under nine minutes remaining.
Young, who had 32 points throughout the first three quarters of Sunday's game, wasn't as explosive when he returned to the game. An MRI on Monday revealed the bone bruise.