The Chicago Bulls have suspended power forward Bobby Portis for eight games after punching teammate Nikola Mirotic in the face. The punch, which happened Tuesday at practice, sent Mirotic to the hospital and left him with a concussion and facial fractures.

The team made the announcement Wednesday, saying that Portis made a mistake.

Portis will serve the suspension beginning with the team’s season opener at Toronto on Thursday and he will be able to practice with the team during his suspension.

Bulls executive vice president of basketball operations John Paxson said Wednesday that Mirotic was going through the procedure the NBA has in place after a player receives a concussion.

“We anticipate Niko being out 4-6 weeks, but needs to clear concussion protocol,” Paxson said in a statement.

Portis struck Mirotic during a heated workout on Tuesday. The two players had been fighting for position during practice, according to USA TODAY Sports' Jeff Zillgitt. The Bulls released a statement that night acknowledging the incident and saying that Mirotic "suffered a concussion and maxillary fractures. Surgery is likely required. Mirotic is out indefinitely."