Bulls' Bobby Portis suspended for punching teammate Nikola Mirotic

— -- CHICAGO -- Chicago Bulls forward Bobby Portis has been suspended eight games after an altercation with teammate Nikola Mirotic during Tuesday's practice led to the latter suffering facial fractures and a concussion.

Bulls President of Basketball Operations John Paxson acknowledged that both players' tempers escalated during Tuesday's practice, ultimately leading to Portis punching Mirotic and knocking him out. Mirotic is expected to miss at least 4-6 weeks.

"Both players owned responsibility in the incident itself," Paxson said. "But only one player threw a punch. And that punch connected and for us that is inexcusable. It's not who we are. It disappoints us in terms of what happened and because of that we've determined that we're going to suspend Bobby for eight games."

The incident is a blow to a Bulls' franchise in the midst of a full-scale rebuild. Mirotic was expected to start in Fred Hoiberg's revamped starting lineup, having beaten out Portis. Now, rookie Lauri Markkanen will get his first career start during Thursday's season opener against the Toronto Raptors.

Both Paxson and Hoiberg spoke of the disappointment they feel as a result of Portis' decision, but the Bulls are hopeful that their young team will be able to rally around each other.

"Bobby Portis is not a bad person," Paxson said. "He's a good kid. He's a competitive kid, but in this instance he made a mistake. And as we all know when you make mistakes you got to suffer the consequences ... this is a team suspension. We did get counsel and advice from the league because this is really unprecedented in a practice situation. There's altercations a lot of times but the result of Niko's injuries are why we've taken the position that we have and that's where we are."

Paxson confirmed that the situation between both players escalated throughout Tuesday's physical practice, with Bulls assistant coach Randy Brown stepping in at one point to try and calm the rising emotions. Both players have under-achieved during their time with the Bulls and have spent three years competing against one another for playing time. The growing tension between the two became too overwhelming to control. Paxson noted that it would be inaccurate to characterize Portis' response as a "sucker punch."

"These type of things do happen," Paxson said. "I've been a part of them. I've seen them. Positionally, it can happen. I used to get into these little scuffles with B.J. [Armstrong] when we played, but you can't cross the line and Bobby crossed the line. And again, the result of the contact and what it's done to Niko is really the thing that has a lot of us sitting here feeling really disappointed in this today."

Hoiberg said he was "very disappointed." He said he went to visit Mirotic in the hospital on Tuesday before he had been released and had spoken to a remorseful Portis in the aftermath of the fight.

"My job is to not let this moment derail us," Hoiberg said. "My job is to get these guys prepared to go out and fight and play as a group. And I'm confident that our guys will do that."

Veteran center Robin Lopez made it clear that the rest of the Bulls' players felt there was blame on both sides of the altercation.

"We talked with Bobby," Lopez said. "Obviously he's regretful about what he did. We talked about it as a team afterwards. Everything was still so fresh. We as a team feel there's blame on both sides. When it comes down to it the punch was inexcusable."