The team announced that Sanders is expected to be sidelined about six weeks.
Sanders got a new four-year, $44 million deal from the Bucks in the offseason.
He averaged 27.3 minutes, 9.8 points, 9.5 rebounds and 2.8 blocks for the Bucks last season. But this year in three games, all starts, he is averaging 17.3 minutes, 2.7 points, 3.7 rebounds and 2.0 blocks under new coach Larry Drew.
Sanders issued a statement on Friday in response to reports of his involvement in a fight.
It read: "I want to start by saying I put myself in a bad situation over the weekend. I didn't make the best decisions down the stretch, but I would like to apologize to my fans here and Sen. Kohl, who I will talk to directly. I've talked to the team and apologized to them, just for shedding a negative light on our team and our organization.
"It's not what we're about at all; it's not who we are. It's not what we stand for. I offer my apologies to everyone, especially the fans. I know they put a lot on me and they count on me a lot.
"For everyone I let down, I'm going to get better, going to be better. I'm going to get better at this, on and off the court. I'm going to come back better. I just thank everyone for their concerns and being patient with me."