The Miami Heat will be without Jimmy Butler with their season hanging in the balance.

Miami confirmed Thursday that Butler has been ruled out for Friday's must-win play-in tournament game against the Chicago Bulls with a right MCL sprain.

Barry Jackson of the Miami Herald added that Butler is expected to be sidelined for several weeks.

Shams Charania of The Athletic and Stadium first reported the news.

The six-time All-Star logged 40 minutes in Wednesday's 105-104 loss to the Philadelphia 76ers but was clearly playing at less than 100 percent for much of the contest.

In the waning seconds of the first quarter, he went up for a shot inside and landed awkwardly on his right knee.

Over the final three quarters, Butler scored 12 points on 3-of-14 shooting, and he was particularly ineffective in the final frame as Miami attempted to fend off the Sixers' comeback.

Fans probably began to expect the worst when he was visibly limping in the tunnel after the game.

The Heat successfully rebounded from a loss in last year's play-in tournament to reach the NBA Finals, but it's tough to see a similar underdog story unfolding this time around.

Miami is already playing short-handed with Terry Rozier missing Wednesday's defeat due to a neck injury. While Duncan Robinson was activated after back trouble forced him out of the lineup, he apparently still wasn't healthy enough to get on the floor against Philly.

Now head coach Erik Spoelstra is looking at an elimination game without his best player. And should the Heat beat the Bulls, Butler's availability in a first-round series against the Boston Celtics would be in serious question.

Game 4 of that matchup is just 11 days away, so even a conservative estimate for "multiple weeks" would put Butler on the shelf for long enough to dig Miami into a deep enough hole it couldn't recover if he were to come back at all.

Unless the MCL injury is less serious than initially feared, it could be a fatal blow to the Heat's conference championship defense.