You can say one thing for sure about the first coaching change of Masai Ujiri’s five-year run atop the Raptors: It was not an easy one, nor a friendly one.

On Monday June 11, Dwane Casey was hired as coach of the Detroit Pistons, one month to the day he was fired by the Raptors after seven impressive years in Toronto. On Tuesday June 12, Nick Nurse officially announced that he will be the Toronto Raptors new head coach. As those significant life events were unfolding, it’s safe to say the two men were not toasting  to each other’s good fortune with champagne and congratulatory repartee. Forget their five largely successful years together on the Raptors bench. Forget that it was Casey who gave Nurse his first NBA opportunity, hiring him out of the developmental league back in 2013. Multiple NBA sources will tell you the one-time mentor and his long-time assistant, have not been on good terms in the midst of Toronto’s coaching-staff shakeup. To be fair, nobody has been in a good mood in here since the season came to its end.

“No love lost between ’em,” said one basketball lifer who would know, speaking of Casey and Nurse.

Nurse is a former coaching journeyman who spent years toiling in the obscurity of the British league before he began his rise to the NBA. He will surely be achieving a longtime goal when he’s introduced this week as the ninth coach in Raptors history and one of just 30 NBA head coaches on the planet. If he had to fray his relationship with one of the most beloved personalities in recent Toronto sports history in becoming what he’s become — maybe that’s the price of success.

Given that Casey, 61, also still counts himself apart the exclusive 30-man NBA coaching fraternity, perhaps it’s not out of the realm of possibility that the old colleagues will eventually bury the hatchet.

At the very least, we could also have an awfully compelling Raptors-Pistons playoff series next spring.

Toronto’s Plan A, don’t forget, was Mike Budenholzer, whose brief interaction with Ujiri ended with Budenholzer taking Milwaukee’s head-coaching job (and a timely ESPN report that the Raptors didn’t offer Budenholzer theirs). Plan B was a month-long coaching search that saw Ujiri interview a hefty list of candidates, among them four-year Spurs assistant Ettore Messina, who was the finalist in what became a two-man race with Nurse.

Hiring the 58-year-old Messina, who built a reputation as one of Europe’s sharpest tacticians during his run to four Euroleague championships as a head coach, would have been an intriguing, bold choice. Hiring the guy who has spent five years sitting beside Toronto’s head coach — after insisting Toronto’s problem against the Cavaliers in the playoffs was coaching — is something less than that.

Not that Nurse doesn’t deserve a good, long chance to prove himself; but it’s worth wondering what measurable new value can Nurse bring to the situation. He was clearly empowered as the team’s offensive co-ordinator. He took an in-season victory lap when U.S.-based writers pointed to Toronto’s newly designed offence — which Nurse got credit for authoring — as the key to an unexpected performance bump that saw the Raptors win the East’s No. 1 seed for the first time in franchise history. But if Nurse was calling out the magic adjustments necessary to beat LeBron James — if he had the answers that could have halted that ugly Cleveland sweep — nobody seemed to be listening.

One league source suggested that on a bench occupied by the defence-first Casey and defensive co-ordinator Rex Kalamian, Nurse’s offence-forward suggestions were never fully heard nor understood. So that’s the argument for making the change. Nurse, the line of thinking goes, couldn’t be the innovator he’s capable of being with an old-school head coach at the wheel. If that’s true we’ll only know the extent of Nurse’s talents when he’s fully strapped into the driver’s seat. Nurse’s supporters expect he’ll find a way to hold players accountable in ways Casey couldn’t. Wish him luck, because he’ll need it.

Following Casey won’t be easy, especially if Ujiri doesn’t back up the coaching switch with a swapping out of key players. You can always nitpick strategy, sure. But higher on the list of the franchise’s problems reside two all-stars who’ve been chronic post-season underperformers and a roster that’s repeatedly bumped its collective head against its competitive ceiling.

What are the odds Nurse can deliver a perceptible upgrade on nothing less than the most successful coach the team has ever employed? And does Nurse have the requisite presence to command the daily stage afforded to an NBA head coach? There are no shortage of doubters. Still, maybe Nurse shouldn’t be underestimated. He has just been rewarded for having the wits to convince Ujiri he’s worth betting on. Soon enough he’ll get a chance to prove it.