Andersen knocked Indiana's Tyler Hansbrough to the court during the second period of Miami's 90-79 win over the Pacers in the fourth game of the series Thursday.
Andersen shoved Hansbrough again and attempted to continue the altercation despite efforts by his teammates to pull him away.
A flagrant foul two was called on the play, but the league office upgraded that to a flagrant foul one after reviewing the video.
Miami, with a 3-2 lead in the series, will be without Anderson Saturday when it tries to clinch a spot in the championship series.
Andersen has made all 15 of his field goal attempts during the conference finals.