A day after the Bucks' 116-100 win over Bulls to wrap up the series, dire news came forth about star forward Khris Middleton's status for the second round.Middleton was diagnosed with a Grade 2 left knee MCL sprain and is expected to miss the entire series against the Celtics, according to Shams Charania.Middleton has not played since suffering the injury just over a week ago. He was originally projected miss at least Games 3 and 4, then sat out Game 5 as well with his team up 3-1 in the series.If Middleton cannot return at any point in the second round, it would obviously deal a big blow to the Bucks' chances to repeat as NBA Champions.The Pro Basketball Docs were originally more optimistic about Middleton's return date, but that was based on the projection of a Grade 1 MCL sprain.Now with the news of a Grade 2 MCL sprain, his mobility would be severely limited even if he returns in the second round.Milwaukee is currently +168 to win the series, with the Celtics at -200, according to FanDuel Sportsbook.