Mirotic suffered a concussion and facial fractures when he was punched by Portis during a practice altercation Oct. 17. Portis was suspended eight games.
According to the reports, Mirotic's team has told the Bulls that they would waive his no-trade clause and leave Chicago rather than stay with Portis. The 26-year-old Mirotic signed a two-year, $27 million contract before the season.
After the fight, the Bulls initially said that they were waiting for Mirotic's concussion symptoms to subside before doctors could ascertain whether he needed surgery for his other injuries. Coach Fred Hoiberg said that Mirotic was not cleared from the concussion protocol when he visited a specialist Wednesday. Vice president of basketball operations John Paxson told reporters at practice Friday that Mirotic was cleared for light physical activity like riding a bike.
Paxson said that the team is sympathetic to Mirotic's plight but would have to do what's best for the organization. He added that they would take Mirotic's lead when it comes to communicating with teammates.
Later Friday, the Bulls said they had picked up the option on Portis' rookie contract. They had been facing a Tuesday deadline.
The picking up of options on players still under their rookie contracts would otherwise be largely a formality for the Bulls, as it is with most teams.
If the Bulls decide to move one or both of the players, neither is likely to have much value throughout the league given their uneven performances over the past couple years.
Mirotic has a team option for next season worth over $13 million if certain escalators in his contract are hit. Portis' deal remains a much bigger bargain, as he's scheduled to make just $2.5 million, according to ESPN's Bobby Marks.
Portis apologized publicly Oct. 21 and said he had reached out to Mirotic but had not heard back.
"I'm wrong for what I did," Portis said. "I want to publicly apologize to Niko. I feel like I let my fans, the Bulls organization and, most importantly, my teammates down. This is not who Bobby Portis is."
In three seasons, Mirotic has averaged 10.8 points and 5.3 rebounds per game as a stretch power forward.
Portis, 22, was a first-round draft pick in 2015 who has averaged 6.9 points and 5.0 rebounds per game over two seasons.
Information from ESPN's Nick Friedell was used in this report.