Four keys to the Milwaukee Bucks winning a second consecutive NBA championship

The Milwaukee Bucks were rallying in the fourth quarter of Game 2 of their first-round series against the Chicago Bulls when a driving lane opened up for forward Khris Middleton.

Middleton made a beeline toward the rim before Bulls center Nikola Vucevic stepped in front of the basket. Middleton attempted to spin away, but his left knee buckled as he fell to the court. Middleton tried to walk it off, but once he exited the game and headed toward the locker room, the team ruled him out for the night.

Middleton was diagnosed the next day with a sprained medial collateral ligament in his left knee. He missed the first round and is expected to miss the entirety of the second round against the Boston Celtics, a series that is tied at 1-1 heading into Saturday's Game 3 (3:30 p.m. ET on ABC).

Middleton's absence poses one of the biggest challenges to the Bucks in their title defense.

The Bucks are 6-1 in the playoffs over the past two seasons when one of their Big Three — Giannis Antetokounmpo, Middleton and Jrue Holiday — is sidelined. But this round against the Celtics marks the first time they have entered a playoff series with an expectation to play short-handed.

Still, the Bucks' goal remains the same: Bring a second consecutive Larry O'Brien Trophy home to Milwaukee.

«We did it last year as a group when Giannis went down [in the conference finals against the Atlanta Hawks],» Middleton said before a team practice a few days following the injury. «Everybody stepped up and played a major part. I expect nothing less.»

If the Bucks struggle to replace Middleton's production, it's more likely than not that they'll see their season come to an end early. But that's far from the only key to raising another banner. Here are three