BOSTON – It was the ideal scenario for Kyrie Irving: a chance to run his own team, the ball in his hands in crunch time, his coach known for giving players the ultimate freedom and no shortage of weapons to alleviate the constant pressure of double-teams.

Irving could have been sent to an also-ran when Cavs General Manager Koby Altman complied with his trade request two years ago. Instead, he went to the most storied NBA franchise — one that had exceeded expectations the previous season with Isaiah Thomas.

Danny Ainge and the Celtics brass knew the concerns with Irving when they dealt for him in August of 2017, and they did their due diligence before pulling the trigger.

“They took a chance with both eyes wide open,” one Cavs source told me.

Moody. Immature. Tough to coach.

“Doesn’t want to listen to anybody,” a Cavs source told me about Irving. “I’ve been around more selfish guys, but when you add up those three – moody, immature and tough to coach – he doesn’t have a leg to stand on.”

But Ainge also understood that you need superstars in order to win championships, and that Thomas wasn’t a bonafide superstar. The Celtics had overachieved in 2017, and there was a ceiling with Thomas as the team’s top player – whether he was injured or not. Irving, who had hit the biggest shot in Cleveland Cavaliers history, was only 25 years old at the time of the trade and there was optimism that he could mature into a leader.

But Irving failed miserably in that department.

Listen, this roller coaster of a season that culminated with four consecutive embarrassing losses to the Milwaukee Bucks wasn’t entirely Irving’s fault. Brad Stevens admitted doing a bad job this season. Gordon Hayward was a shell of himself on most nights, and the young guys who tasted stardom a year ago didn’t buy into being relegated to role players while Irving took control.

A year ago at this time, the Celtics were fun to watch. They played with heart, energy, enthusiasm and both mental and physical toughness. Sure, there were virtually no expectations once Irving joined Hayward on the injured list, but the core of Al Horford, Jayson Tatum, Jaylen Brown and Terry Rozier, Marcus Smart, Marcus Morris and Aron Baynes was one win shy of the NBA Finals.

This team was anointed as the favorite in the preseason to win the East. It made complete sense – LeBron was off to Los Angeles, and Boston added Irving and Hayward back into the fold.

But Irving was a chemistry-killer with no semblance of leadership qualities who would call out his younger teammates publicly and even do the same with his coach.

“Everyone respects his talent,” one Celtics player told me earlier this season, “but he’s hard to play with. It’s all about him.”

When Irving told Celtics fans at an event in early October that he planned on re-signing with Boston this offseason, they rejoiced. This was the cornerstone of the franchise, the guy who would help them hang banner No. 18 in the Garden.

Now most fans are tired of his act off the court, and disappointed in his performance on it.

He downplayed the regular-season, putting all the emphasis on the postseason — a time in which he had shined with the Cavs. But those came with the best player on the planet. Now it was on him to show he could be the guy.

Instead, after a terrific all-around performance in the series-opener, Irving was completely outplayed and outclassed by Bucks guards Eric Bledsoe and backup George Hill throughout the final four games – all losses. Irving shot just 25-of-83 (30 percent) from the field and 5-of-27 (19 percent) from 3 and looked so ordinary that some even questioned whether he was injured.

Then there were the postgame condescending news conferences. I understand some of the questions tossed Irving’s way are awful, many in bad taste, some that can’t be answered with truthfulness in fear of the repercussions. But Irving never took accountability for his piss-poor performance(s), instead making himself less likeable and human with his comments.

“I’m trying to do it all,” he said after Game 4. “Twenty-two shots, I should have shot 30. I’m that great a shooter.”

If he really is a basketball genius – as he proclaims himself to be – he’d make better decisions on the court. When the shots aren’t falling, as was the case on Wednesday night, he’d set up his teammates. He’d make sure that the young guys are content, and that Hayward has some much-needed confidence. He’d make sure not to be a liability on the defensive end of the court.

But it’s all about Kyrie.

Now the Celtics will likely sit and wait, at the mercy of Irving and his decision whether to re-sign with Boston or head somewhere like New York, which has been speculated for months. Sure, Ainge could elect to not put forth a max contract offer, but it’s far more likely that he puts one on the table and hopes – in secret and only on occasion – that Irving chooses to play elsewhere.

There’s also the chance that Irving doesn’t want to leave in this manner, doesn’t want to leave money on the table, and decides to give it another shot in Boston. Maybe replacing Rozier and Morris with two players who better accept their roles, and with Hayward becoming closer to the old Hayward, roles will be clearer.

And maybe Irving will change, although that’s highly unlikely since he took no accountability on Wednesday night after the loss. Even if nothing changes and the chemistry remains a mess, the Celtics could easily move Irving, say, midway through next season.

But most NBA sources feel as though the marriage between Boston and Irving is on the verge of a divorce after a brief honeymoon period. Few in Boston will be sad to see him go, whether it’s the fans or even his teammates. This team had become difficult to like – and the primary reason was Irving.

While Thomas had won over the city with his toughness, passion and a chip on his shoulder, Irving was almost the polar opposite: miserable, entitled and uber-talented.

“He takes the air out of the locker room,” another member of the Celtics organization said. “And you just never know what you’re going to get with him.”

Actually, you know exactly what you’re going to get. The same old Kyrie.

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