Since ousting Detroit from the playoffs Monday, the Bulls had been thinking that the behavior of the Pistons throughout the series-and especially that of Dennis Rodman in Game 4-was pretty sorry.

On Wednesday, Rodman said he was sorry. He also was fined $5,000 by the NBA office.

Rodman, who flagrantly pushed Scottie Pippen out of bounds in Game 4, sent a letter of apology to the Bulls forward, who suffered a six-stitch gash in his chin when he was knocked down. Later in the day, the league announced the fine but said Rodman would not be suspended.

''We looked at the facts and made a judgment,'' said NBA operations director Rod Thorn. ''We had our security people investigate, and we feel he was seriously contrite. The fine was for pushing Pippen.''

Thorn said Rodman should have been assessed a technical foul on the play. But he said it ''was debatable'' whether Rodman should have been ejected.

''There was no punch,'' Thorn said. ''He just shoved him. It wasn`t in the best interests of the game, but it was not to the degree that a suspension was warranted, although we talked about it.''

''I`m not convinced he wrote it,'' Pippen said. ''If he did, it`s a confession, but I don`t believe it`s going to make up for the scar I might have on my chin.''

Copies of the letter were sent to the Bulls, NBA officials and Chicago, Detroit and national media. It was written on Pistons stationery, and club officials said Rodman had approached them about writing it.

Bulls coach Phil Jackson said: ''We accept his apology, but we won`t forget the incident. You accept the apology at face value.''

Michael Jordan, who had been critical throughout the series about the Pistons` tactics, said: ''As a team, we`ve forgotten about that. We beat them and achieved something. We`ll deal with Detroit when we play them again.''

The Pistons have been getting a bashing in the national media. New York Times columnist Ira Berkow wrote that Chuck Daly should not be allowed to coach the 1992 Olympic team because he permitted the Pistons` rough tactics. And in Game 5 of the Western Conference finals, NBC-TV questioned Detroit`s behavior.

TEXT OF RODMAN`S LETTER

May 29, 1991

Mr. Scottie Pippen

Chicago Bulls Basketball Team

980 North Michigan Avenue

Suite 1600

Chicago, Ill. 60611

Dear Scottie,

I am writing this letter to apologize to you for the incident that happened in Monday`s game. You are a great player and I`m glad you weren`t hurt by the incident. It was merely one of frustration.

I am not the type of player of which I have been accused. The situation was one of those things which should not have happened. I am ready and willing to accept any fines or consequences set by the league for my actions.

I sincerely apologize to you, your teammates and the entire Chicago Bulls organization. I also hope that there are no hard feelings between you, your teammates and me.

Good luck in the NBA Finals-it`s a tough road ahead of you.

Sincerely,

Dennis Rodman