CHICAGO -- A 15-year-old boy accused of attacking a Kansas City Royals coach during a game pleaded guilty and was released to his family.

The boy and William R. Ligue Jr. were charged in the September beating of coach Tom Gamboa during a game between the Royals and the Chicago White Sox.

Assistant Public Defender Vincent Akers said the boy pleaded guilty Monday to one charge of aggravated battery and two counts of mob action for striking Gamboa and an off-duty state trooper who was working security at the game. At his sentencing Nov. 7 he could face probation or incarceration until he is 21, Akers said.

Cook County Juvenile Court Judge Paul Stralka released the boy, whose name was withheld because of his age, from the Juvenile Temporary Detention Center.

The teen told the court he was sorry for what happened and wanted to go home with his mother and go to school, said Marcy Jensen, a spokeswoman for the Cook County state's attorney.

Ligue remains in jail. His sister, Kimberly Richardson, said he has struggled since his month-old daughter's death in May. Richardson called the sprint onto the field at Comiskey Park "a cry for help."