The league has health and safety protocols.
Game 5 of the best-of-seven series is scheduled to take place on Wednesday. The first-round game can be won by Milwaukee with a win.
This is another blow for LaVine, who sat out 15 games this season with knee and back injuries, and has seen other Bulls miss significant time.
LaVine made his second straight All-Star Game and is one of Chicago's go-to options.
He shot 48.6 percent from the field and 38.9 percent from deep, and averaged 24.4 points, 4.5 assists, and 4.5 boards per game.
He is scoring 19.3 points per game.
If LaVine is out, the Bulls will rely on their other players to score even more, while Coby White and Ayo Dosunmu will likely see more playing time as the team tries to keep their season alive.