The Knicks' Mitchell Robinson dunks the ball against the Orlando...

The Knicks' Mitchell Robinson dunks the ball against the Orlando Magic on April 3, 2022. Credit: AP/John Raoux

Less than 24 hours after reaching agreement with two important newcomers, the Knicks circled back and came to terms with their own free agent — agreeing on a four-year, $60 million deal with Mitchell Robinson.

A league source confirmed the deal, first reported by ESPN, which brings back the starting center and essentially finishes off free agency for the Knicks.

They added a starting point guard in Jalen Brunson and a backup center in Isaiah Hartenstein and now have secured the anchor to coach Tom Thibodeau’s defense.

Suitors for Robinson’s services evaporated as Detroit landed Jalen Duren on draft day and Dallas opted to sign JaVale McGee.

There was some question of just how high the Knicks would go for Robinson, who has steadily improved defensively but remains an offensive threat only as far as the reach of his arm. But Thibodeau treasures rim protection, and Robinson is among the best at that. And with the trade of his backup, Nerlens Noel, the Knicks had no option but to bring Robinson back.

Robinson, 24, was a find of the previous front office. He skipped the chance to play in college and was a second-round selection in 2018.

While he has improved under Thibodeau, Robinson also has been slowed by injuries. He played only 31 games in the 2020-21 season, suffering a broken hand and then a broken foot.

The foot injury limited his ability to work on conditioning last summer. Even though he used the time to build his upper-body strength, he struggled to regain his usual athleticism and speed for much of last season. That gradually returned, and the Knicks will need every bit of it next season.

Robinson could be returning to a starting lineup that includes a backcourt of Brunson and Evan Fournier — hard-working players but hardly defensive stoppers.

In his interview on MSG Network at season’s end, Knicks president Leon Rose said of Robinson’s injuries: “Mitchell had a phenomenal year, was our anchor on defense and really took a nice step this year. And even showed us a little bit on offense .  .  . Everything is taken into account. You have to look at that. You have to look at the injury history. You have to look at all those things in making your decision, but for the most part, I thought he did a really good job this year.”

Robinson averaged 8.5 points and 8.6 rebounds last season and shot 76.1% from the field. That would have broken his own NBA record of 74.2% set two years earlier, but he did not have enough field goals to qualify for the league leadership.

The deals with Brunson and Hartenstein cannot be officially signed until Wednesday, and the structure remains uncertain with the possibility of sign-and-trade agreements that could change the Knicks’ salary-cap status.

Right now, it appears they are capped out, having just the midlevel exception of $5.4 million and the ability to sign veteran minimum deals.

Second-year center Jericho Sims is expected to be shifted from a two-way contract to a regular roster spot, leaving one remaining spot available.