Spending at least £60m in transfer fees on a 30-year-old, giving him a salary of up to £350,000-per-week, and signing him to a four-year contract with the option of a further 12 months would not typically be viewed as cost-effective business.
That is at least partly why Manchester United will not be triggering said option in Casemiro's contract. His Old Trafford career will instead come to an end this summer, as had long been expected.
Once he says goodbye, after adding to his 146 appearances, many will hold up Casemiro's time in Manchester as another symbol of United's waste and extravagance in the transfer market, and a starry-eyed infatuation with big-name, big-money players who arrive well past their peak.
There is undoubtedly some truth to that, but even if he may not have been a particularly smart signing, Casemiro was arguably a necessary one. And though four seasons of a five-time Champions League winner was never going to come cheap, it would also be unfair to dismiss him as a costly mistake.
If anything, the cost was a symptom of United's desperation and dysfunction during Erik ten Hag's tumultuous first summer in charge, with his signing from Real Madrid being quickly accelerated after back-to-back defeats in their opening Premier League games.
The long, protracted and painful pursuit of Frenkie de Jong had run aground by that point. Champions League qualification needed to be delivered at all costs.
Ultimately, it was, thanks in no small part to Casemiro. For that first year in Manchester, certainly for the first six months of his Old Trafford career, he was considered a transformative addition.
The arrival of one of the best No 6s of his generation finally addressed a longstanding problem at the base of midfield. Even if his age meant he was not going to be a long-term solution, his quality and experience meant he was a quick, effective fix.
At his best for United, around the time of the Carabao Cup final victory over Newcastle United that February, he was being uncontroversially hailed in some quarters as the club's most important signing since Eric Cantona.
Casemiro's second season was much more of a struggle, though, and has coloured perceptions of his United career away from Old Trafford. On several occasions, he no longer looked capable of keeping up with the pace of the Premier League, and those stuck in the craw.
Though far from the only player to have difficulties meeting the demands of Ten Hag's increasingly helter-skelter style of play, it did him absolutely no favours as a holding midfielder on the wrong side of 30 and exposed the short-termism of his signing.
That was never more evident than on the night of United's 4-0 defeat at Crystal Palace in May 2024, when Sky Sports pundit Jamie Carragher memorably implored Casemiro to "leave the football before the football leaves you".
He didn't, though. And even after being cast to the peripheries by Ten Hag's successor, at one stage finding himself behind a 21-year-old Toby Collyer in the pecking order, his dedication and determination to win back his place led him to practically become an ever-present again. From then on, he was an example Ruben Amorim would constantly tell his other players to follow.
Last week, The Athletic revealed that Casemiro's option would be automatically triggered if he started every remaining game this season. The chances of that were remote. Even if United had been open to another year, even if their shrinking budgets could afford it, injury or suspension would likely have got in the way. But on form alone, it was not such an outlandish prospect.
Casemiro has started 19 of 24 matches in all competitions this season, including all but one of the Premier League games that he has been available for. Despite the justified clamour for Kobbie Mainoo to be given more opportunities, few argued that should come at the 33-year-old's expense.
When part of more compact and conservative tactical setups than Ten Hag's, he has generally looked capable of continuing to play at a high level.
His considerable threat from set pieces has left him with a respectable tally of 21 goals since joining. And though he could be erratic with his passing, there were often nights over the past three and a half years when he looked like the only United player other than Bruno Fernandes capable of creating something.
Thursday's announcement that he will leave at the end of the season followed a man-of-the-match display in the 198th Manchester derby. It was only the latest example that Casemiro still has something to offer United, albeit not on his current pay packet.
Even without the one-year option triggered, a rough estimate puts the minimum cost to United of first signing and then keeping Casemiro for the past four seasons at £119m ($160m). Was it worth it? Opinions will vary.
But here's something more of us can agree on: United have been a better team when Casemiro is playing. This season, especially. And now, he must be replaced.
There is a different set of decision-makers in place at Old Trafford compared to the summer of 2022, and they will surely look for a younger and more athletic midfielder, with a higher ceiling in terms of what they can achieve as a United player, and a higher resale value if they fall short of that mark. A smarter signing, we'll all surely agree.
Like Casemiro, that midfielder - whether it is Elliot Anderson, Carlos Baleba or another target - won't come cheap. And to avoid any sort of drop-off next season, they will need to be as dependable at the base of United's midfield as the man they are replacing has been for most of his eventful Old Trafford career.
This article originally appeared in The Athletic.
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