Conor McGregor appeared at Brooklyn Criminal Court on Thursday and had his next hearing set for July 26.
The disgraced UFC star touched down in America this week to face charges of assault and criminal mischief, alongside his co-accused and gym team-mate, Cian Cowley.
McGregor and Cowley told the court they planned to negotiate a plea deal.
The melee injured several fighters and forced the UFC to cancel several bouts scheduled for that weekend.
McGregor was arrested and charged after the attack, but was released on bail and ordered to return to the US on June 14 for a court hearing.
I regret my actions that led me here today, I understand the seriousness of this matter and Im hopeful it gets resolved soon. Thank you every one, McGregor told reporters afterwards.
The 29-year-olds appearance in court lasted no longer than a minute and he will return to Brooklyn again next month.
The UFC have yet to punish McGregor, a two-weight UFC champion, for his actions as they await the outcome of the criminal charges.
UFC boss Dana White revealed he would be meeting with McGregor after the Brooklyn hearing, in what is believed to be the first face-to-face between the pair since the incident in April.
He and I are meeting on the 18th of this month, White told TMZ. I dont know whats gonna happen. I dont know what Conor has planned. I dont know what Conor and his team have worked on.
McGregor attacked a bus carrying rival UFC fighters last April in the build-up to the promotions UFC 223 event in Brooklyn.