Milwaukee Bucks star Khris Middleton will miss the rest of the opening-round playoff series against the Chicago Bulls due to a sprained medial collateral ligament in his left knee, sources told ESPN on Thursday.

Middleton will be re-evaluated in two weeks when a timeline on his possible return in these playoffs -- if the Bucks advance -- could become clearer, sources said.

Middleton underwent an MRI in Milwaukee on Thursday after suffering the injury in the fourth-quarter of the Bucks' Game 2 loss to the Bulls. The Bucks head to Chicago on Friday for Game 3 with the series tied at 1-1.

Over the past two seasons, the Bucks are 86-34 (.717) when Antetokounmpo, Middleton and Jrue Holiday are all on the floor together, including the playoffs. However, Milwaukee did outscore opponents by 7.8 points per 100 possessions when Antetokounmpo and Holiday played without Middleton on the floor.

A three-time All-Star, Middleton averaged 20.1 points, 5.4 rebounds and 5.4 assists while shooting 37% from 3 this season.