Grunfeld said the pair were suspended for the Wizards' game Sunday against San Antonio after an investigation into an alleged altercation outside a night club.
"After further investigation into an incident on Thursday night, we concluded that Andray and JaVale conducted themselves in an unprofessional manner. As a result, both players will be suspended for tomorrow's game at San Antonio," Grunfeld said in a released statement.
The Washington Post cited multiple unnamed sources saying the pair exchanged punches Friday outside the Shadow Room in Northwest Washington early Friday and that police had to be called in to break up the altercation.
No arrests were made in incident, a source said.
Grunfeld, however, denied that Blatche and McGee had been in a fight, telling the newspaper that "only one push" was made as other disturbances were happening inside the club.
Blatche is the Wizards' leading scorer, averaging 16.8 points and 7.7 rebounds per game. McGee has averaged 9.2 points per game and is the team's top rebounder with 8.3 boards per contest.