Police spokesman Richard French says the 47-year-old actor was arrested Wednesday night in the downtown area. French did not have details of the incident.
French said Sizemore remained jailed Thursday morning. His bail was set at $20,000.
Sizemore couldn't immediately be reached for comment. Representatives for two agencies listed as representing Sizemore said they no longer did so.
He's also had a string of drug-related arrests in recent years.