Tyler Herro will miss Friday's elimination game in Boston because of a left groin strain.
This will be the third game in a row that Hero will spend on the bench due to this issue.
Without Herro, Miami has lost each of the last two games and is now 3–2 behind in elimination.
In place of Hero, Duncan Robinson's role has increased, and he has scored 25 points in 50 minutes in the last two games.
Herro had a good third season with Miami Heat, with average a career-high 20.7 points, five rebounds and four assists.
Those numbers helped earn him the NBA's sixth Man of the Year award in 2022.
So far in the NBA playoffs, the Herro have scored a total of 13.5 points per game, plus 4.1 rebounds and 2.9 assists.
Miami has struggled aggressively in his absence, averaging 81 points in the last two games – both Boston won.
The Heat shot just 33.3% from the floor in Game 5.
“He’s definitely made progress, but he’s not quite ready,” Heat coach Erik Spoelstra said before Friday’s must-win showdown.