The San Francisco district attorney's office says 21-year-old Paola Pavone is due back in court Friday after entering the plea last week. Pavone is charged with felony possession of a destructive device in a public place, felony possession of combustible material and misdemeanor discharging dangerous fireworks.
A message seeking comment was left for Pavone's attorney Monday afternoon.
Police say several people suffered minor injuries when Pavone threw the firework into a group of people near a concession stand during the game on Wednesday.
The injuries included dizziness and temporary loss of hearing.