The Missouri Highway Patrol says the extra reinforcement is to add security to Busch Stadium as the St. Louis Cardinals return from a road trip.
The violence began after an unarmed African-American teenager named Michael Brown was shot by a police officer on Saturday night.
That officer’s name has not been released, as officials say his life and his family’s lives could be in danger if his identity is made known.
The FBI and St. Louis County police are both investigation the incident. County prosecutor Bob McCullouch says it could be several weeks before the investigation and concludes and charges are filed.