Knicks guard Immanuel Quickley ‘doubtful’ to play in do-or-die Game 6

MIAMI — Reinforcements don’t appear to be coming for the Knicks’ backcourt.

Immanuel Quickley is listed as doubtful with a sprained left ankle, the team announced Thursday, making Game 6 likely the third straight game the super-sub will miss.

Without Quickley, coach Tom Thibodeau went with his starting backcourt of Jalen Brunson and Quentin Grimes for a full 48 minutes in Wednesday’s Game 5 victory at the Garden.

Grimes was briefly shaken up in the fourth quarter after bumping knees with Heat big man Bam Adebayo, but he stayed in the game. He wasn’t listed on the injury report.

Grimes and Brunson became the first Knicks duo to play a full 48 minutes in a playoff game since Jerry Lucas and Walt “Clyde” Frazier in 1972.

“It says a lot about them,” Thibodeau said.

Asked if he planned to operate the same way on Friday night in Miami, the Knicks’ coach said: “We’ll see what Game 6 brings. If it requires them to do that, then I’m not afraid to do it. If we have other players available, we’ll just see how it goes.”

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There has been one common denominator in the Knicks’ two wins in this series: Dominance on the glass. In their victories in Game 2 and Game 5, they have out-rebounded the Heat by 16 in each contest. It was a major part of the Knicks’ success in their five-game, opening-round series win over the Cavaliers.

“The rebounding is big in this game,” Thibodeau said after Wednesday night’s win. “I think obviously we gotta get our turnovers down. But I think that the rebounding, that’s a big part of our defense, and we gotta continue to make sure that we prioritize it.”

The Heat listed Jimmy Butler (sprained right ankle), Caleb Martin (back contusion) and Haywood Highsmith (left knee tendinitis) all as probable.