Knicks center Mitchell Robinson dunks past Raptors forward Pascal Siakam...

Knicks center Mitchell Robinson dunks past Raptors forward Pascal Siakam and forward Scottie Barnes in the first half of an NBA game at Madison Square Garden on Monday. Credit: Kathleen Malone-Van Dyke

ATLANTA — The Knicks’ turnaround from a lottery-bound team in turmoil to one battling for playoff positioning came when coach Tom Thibodeau shuffled the rotation, focusing on his preferred style of play, with a clear emphasis on defense.

But the Knicks — with two straight losses behind them and games awaiting in Atlanta and Toronto — will have to soldier on without Mitchell Robinson, the anchor to that defense.

According to the team, Robinson underwent successful surgery to repair a fractured right thumb Thursday, an injury suffered in the opening minutes Wednesday night in a loss to the Washington Wizards. Robinson will be reevaluated in three weeks.

The injury originally was called a sprain and the team disclosed the fracture Thursday.

Robinson suffered a fractured bone in his right hand in February 2021 and was sidelined for five weeks after undergoing a surgical procedure.

For now, the Knicks’ focus is how to survive this extended stretch without Robinson.

Isaiah Hartenstein was signed in the summer as the primary backup to Robinson. He started seven games this season — six during Robinson’s previous absence (with an ankle injury) and then in the game that Robinson returned to action.

Jericho Sims got two starts in place of Robinson but was pushed out of the rotation for five straight games when Obi Toppin returned from injury until Robinson went out of the game nine minutes in Wednesday.

“It’s just the next guy,” Thibodeau said after Wednesday’s game. “I love the depth that we have at center — Isaiah and Jericho, Julius [Randle] can play the five. We have three guys that are more than capable.”

Filling the minutes is one thing, but finding a person to serve as the back line of the defense is another.

The Knicks are 21-17 with Robinson on the court and 4-4 without (those numbers change to 21-16 and 4-5 if you include his quick exit Wednesday). The team’s net rating with Robinson on the floor is the highest of any player on the team — 8.2 points per 100 possessions.

“It’s a big impact,” Jalen Brunson said. “Mitch is a presence down in the paint. Obviously, we want him to have a speedy but healthy recovery. But we want him at 100%.”

“Mitch is really the anchor for our defense,” RJ Barrett said. “Him going out, it’s an adjustment for sure. With everything, the rebounds, blocked shots, also just the factor people don’t want to go in the paint as much against him . . . You’re losing that with him, all the offensive rebounds he gets. He’s a big part of our team.”

Sims plays a style that is more similar to Robinson and Hartenstein provides more offensive skill with the second unit. Thibodeau said he has not yet decided which way he will go Friday night against Atlanta.

“I want to think and see more, think it through in terms of what’s best for both groups, what will make it function best,” he said. “Both guys have gone back and forth. We’ll get a chance to look at it deeper and make a decision.”