CHICAGO -- The teenager who ran on the field with his father during a game and attacked Kansas City Royals coach Tom Gamboa will spend at least two more weeks in custody.

The 15-year-old boy's lawyer was granted a request Tuesday for more time to gather evidence. A trial date has not been set.

The teenager is charged with aggravated battery, a felony.

If he is convicted, the boy's sentence could range from probation to five years in a youth detention center, Assistant State's Attorney Catherine Gregorovic said.

After Tuesday's brief hearing, Assistant Public Defender Christopher Swanson would not say why he didn't ask the judge to release his client from a juvenile facility. The boy's mother refused to comment.

At Swanson's request, the judge ordered a television station to save its tape of Thursday's game between the Royals and White Sox at Comiskey Park. The lawyer said he would subpoena the tape.

During the ninth inning, the 54-year-old Gamboa was coaching first and facing the field, when two shirtless men rushed him from behind. They knocked him to the ground, where they punched and kicked him.

On Saturday, the teenager's father -- 34-year-old William Ligue Jr. -- was held on $200,000 bail. Ligue faces the same felony charge as his son and could be sentenced to up to five years in prison if convicted.