Toulouse lock Trevor Brennan said he regrets climbing into the stands to punch a fan but that he was provoked by a group of Ulster supporters.
The 33-year-old former Ireland international said the visiting Northern Irish fans insulted his mother and poured beer on him as he warmed up on the sidelines during Sunday's Heineken Cup match at Toulouse's Stade Ernest Wallon.
"I then climbed the wall and had an altercation with this person," Brennan said in a statement Tuesday. "I regret this incident. But I didn't initiate it. That is the last thing I wished to do. ... I love rugby, I love Toulouse and the supporters, but I love my family and my mother more than all that."
Brennan punched 25-year-old Patrick Bamford, an accountant from Belfast, Northern Ireland, who now lives in London. Bamford was examined by the Ulster team doctor after the match and received medical treatment after returning home, the team said. No serious injuries were reported.
The tournament organizers, European Rugby Cup, have opened an investigation. Brennan could face a long suspension and heavy fine.
Toulouse also said that Ulster fans insulted Brennan and sprayed him with beer. Some media reports said the fans also shouted slogans about a bar that Brennan owns in Toulouse.
"Trevor Brennan is a generous player and has always respected his opponents and their supporters," Toulouse said in a statement Monday.
The club said it would ask the European Rugby Cup to investigate the Ulster fans' behavior, reports AP.
"Such fans have no place in the sports stadium, and even less place in a rugby stadium," the statement said.
Ulster, meanwhile, called the incident "disgraceful" and said Brennan had "tarnished the game of rugby football."