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John Paxson, the Chicago Bulls executive vice president of basketball operations, announced Wednesday that Nikola Mirotic will miss the first four to six weeks of the regular season and needs to clear the NBA's concussion protocol before making his 2017-18 debut.

ESPN.com's Adrian Wojnarowski reported Tuesday that Bobby Portis punched Mirotic during an altercation between the two players. According to Wojnarowski, Mirotic "stayed down several minutes" after the incident ended.

In an official statement, the Bulls confirmed Portis and Mirotic "had a physical altercation." Paxson confirmed Wednesday that Portis is suspended for eight games. The Athletic's Darnell Mayberry shared his comments from the team's practice:

Mirotic averaged 10.6 points per game and shot 34.2 percent from beyond the arc for Chicago last season. The Bulls signed him to a two-year extension in the offseason. Mirotic will earn $12.5 million guaranteed this year and has a $12.5 million team option in 2018-19.

Between Mirotic's injury and Portis' suspension, Lauri Markkanen is poised to start at power forward for the Bulls in their opener against the Toronto Raptors on Thursday.

In his one year at Arizona, Markkanen averaged 15.6 points and 7.2 rebounds a game. He also a 42.3 percent shooter from beyond the arc.

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