When Tyson Chandler steps onto the court tonight against the Indiana Pacers, the Bulls' rookie forward will be facing what could be his biggest obstacle of the season.

It won't be Reggie Miller or Jermaine O'Neal or Jalen Rose, but NBA officials.

Chandler, 19, played 13 minutes Wednesday against the Los Angeles Clippers before fouling out with two points and no rebounds. Chandler is good enough to deal with the speed and strength of opponents. But dealing with the temperament of NBA officials is complex, especially for someone jumping to the league from high school.

''When you're in high school, you get star treatment and you're a favorite with the refs,'' Chandler said. ''The refs are on your side and are willing to talk to you, and you're at a level that you dominate.