The suspension will take effect immediately and will extend through the team's Dec. 17 contest against the Indiana Pacers.
Ellis suffered an ankle injury during an accident while riding on a moped during the offseason and was already expected to miss at least three months of the season.
"The cooperation that we received from Jeff Fried (Monta's representative) enabled us to be very diligent in collecting all of the facts surrounding the incident," Rowell said. "This 30-game suspension is a result of that. From this point forward, it is the complete focus of everyone involved to provide Monta with all the support he needs to have a successful rehabilitation, and to get him back on the court as an integral part of this team."
The Warriors will host the Oklahoma City Thunder at ORACLE Arena tonight at 7:30 p.m. Robert Rowell will be available to the media at 6:15 p.m. prior to the game in the Interview Room.