Malcolm Brogdon unavailable off Celtics bench for Game 6 because of right forearm strain

While the Heat had Gabe Vincent (ankle) back for Game 6, the Celtics were without Malcolm Brogdon (forearm).Jim Davis/Globe Staff

MIAMI — Celtics guard Malcolm Brogdon was ruled out for Game 6 of the conference finals against the Heat on Saturday night because of a right forearm strain.

Brogdon, who last month was named the NBA’s Sixth Man of the Year, was listed as probable prior to Game 1 before eventually being cleared to play, and he scored 19 points in a loss. He added 14 points and four rebounds in the Celtics’ Game 2 loss, but has struggled mightily in the three games since, totaling just 2 points on 1 for 13 shooting.

He sat out the second half of the Celtics’ Game 5 win due to the injury and has declined interview requests during the Celtics’ last two open media availabilities. Coach Joe Mazzulla hasn’t shed much light on his status, either.

Mazzulla said about 90 minutes before tipoff Saturday that Brogdon was going through a workout to determine his availability, and he was officially ruled out about 30 minutes later.

Brogdon averaged 14.9 points, 4.2 rebounds, and 3.7 assists in the regular season while connecting on 44.4 percent of his 3-pointers, serving as the anchor of the second unit.

In Brogdon’s absence, guard Derrick White saw his minutes increase from a postseason average of 28.6 to 42. That 42nd minute proved to be the difference for the Celtics when his putback at the buzzer won Game 6, 104-103.

Heat guard Gabe Vincent, who missed his team’s Game 5 loss because of a sprained ankle, returned for Game 6 and scored 15 points.

Williams in bigger role

Mazzulla and forward Grant Williams developed a strong relationship during Mazzulla’s time as an assistant, and that bond has helped them navigate some challenging circumstances for Williams over the course of this season.

Williams’s opportunities have been inconsistent, with him going in and out of the rotation. Even during these playoffs, he did not play in five of the Celtics’ first 14 games and received just spot minutes in several others.

But he has emerged as a central piece of the rotation recently. Williams entered Game 6 averaging 27.8 minutes, and he has taken advantage of the opportunity, connecting on 58.3 percent of his shots and 53.3 percent of his 3-pointers. In Game 6, he played 22 minutes as one of three bench players to see time.

“I appreciate his humility and professionalism to understand how it works and always being ready to play,” Mazzulla said. “We have each other’s back. We have a level of communication and trust with each other that we can just communicate exactly what’s going on. So from day one, he’s had a trust factor, he’s had a humility and a professionalism.”

Williams said his approach does not change whether or not he is playing.

“Just being there for your teammates, that’s the No. 1 thing, whether it’s on the floor or off,” he said. “For me, it’s just trying to stay mentally disciplined in my regimen, making sure I’m prepared both on and off the court, both diet and also with the actual workouts and stuff that I’m doing to stay consistent. And I think that I’ve been very fortunate to have a lot of great teammates throughout this year, and they’ve had my back throughout anything that’s happened. It’s my job to do the same for them.”

Butler everything to Heat

The momentum in this series had clearly shifted in Boston’s favor heading into Game 6, but the Heat remained confident, in large part because they were following their veteran leader, Jimmy Butler, who never appears fazed by big challenges.

“Jimmy leads with everything — his spirit, his soul, his competitive nature,” Heat coach Erik Spoelstra said before the game. “It’s all out there on his sleeves. That’s what we love about him.

“I mentioned to him, when I first met him, and then in the subsequent years after that, he never has to apologize, ever, for who he is and what he is about. It’s the same language as us, and that’s why we’re all following him.”