Report: Mirotic was aggressor in fight with Portis

It was Bobby Portis who finished the fight between Chicago Bulls teammates on Tuesday, but it was reportedly Nikola Mirotic who started it.

Mirotic and Portis had been jawing at each other for most of the Bulls' practice, but Mirotic helped escalate the affair by charging at Portis twice, sources told ESPN's Adrian Wojnarowski. After the second time, Portis threw the fateful punch that fractured Mirotic's maxillary bone and sidelined him indefinitely.

The two power forwards have had a fraught relationship since Portis entered the league in 2015, as they've battled for playing time at the position, according to CSN's Vincent Goodwill.

As the Bulls work with the NBA to determine disciplinary action for the incident, Portis has a phone call scheduled with league officials on Wednesday, sources told Wojnarowski.

With a suspension almost certainly on the way, the Bulls will be without the top two power forwards on their depth chart when they open the regular season Thursday night.