"It's unfortunate. I feel very bad for Mike. I know how badly he wanted to get this season started in the right way. He's down right now," said Miami coach Erik Spoelstra.
Miller, who signed a five-year deal with the Heat in July, averaged 10.9 points per game with the Washington Wizards last season and shot 48 percent from three-point range.
The Heat open their regular season on Tuesday against the Boston Celtics.
(Reporting by Mike Mouat in Windsor, Ontario. Editing by Frank Pingue)