Thomas slammed after saying contest about money
He later apologized "for any negative feelings that may have been caused by my comments."
Wednesday, Thomas told reporters that his words just came out wrong.
"It was a miscommunication and understanding of words," Thomas said. "I take it as a lesson learned. I hate that this happened. I don't want to give a bad impression. I didn't even think I said it in a way to make it be as if I was saying, 'OK, I'm going out to get a check, and that's it.' I didn't [want to make it] like that at all."
Bulls coach Scott Skiles said Thomas "has to mature more."
"These are the kinds of episodes we all can mature from. We've all said things we've regretted as soon as they came out of our mouth," Skiles said. "You can be honest with the media and not guarded all the time ... if you have something bright to say."
The first Bulls player since Scottie Pippen in 1990 to participate in the event, Thomas was quoted in Tuesday's editions of the Tribune as saying: "I'm just going to go out there, get my check and call it a day."
When asked if being around some of the game's greats could be beneficial for a rookie, he responded, "I'm just into the free money. That's it. I'll just do whatever when I get out there."
The winner of the Feb. 17 event in Las Vegas gets $35,000. The runner-up earns $22,500, with the third and fourth-place finishers getting $16,125. Joining Thomas are defending champion Nate Robinson of New York, Orlando All-Star Dwight Howard and Boston's Gerald Green.
"This fine is an appropriate response to the remarks Tyrus made concerning his participation in the slam dunk contest," Bulls executive vice president of basketball operations John Paxson said in a statement. "It is a poor reflection on Tyrus individually and a poor reflection on the Bulls organization, and I am certainly disappointed."
Thomas apologized in a statement issued through his agents Tuesday night.
"I truly feel honored to be invited to participate in this year's slam dunk contest during next week's NBA All-Star Weekend in Las Vegas," Thomas said. "The opportunity to represent the Bulls and the city of Chicago on a global stage is a privilege that I do not take lightly. I regret the extent to which my comments indicate otherwise."
Thomas has appeared in 41 games, averaging 3.5 points and 2.7 rebounds.
The Associated Press contributed to this report.