As with most of United's signings over the last decade, the issue wasn't necessarily the transfer itself, but the lack of thought for how to utilise the player before/after the deal had been made.
Casemiro at 31 years of age needs a capable deputy to help him manage his minutes; preferably a younger player who could be moulded into his longer-term replacement. And while someone like Kobbie Mainoo looks an excellent prospect, he's likely too young to fill in for this deputy role, and would probably be better served being slowly introduced as the number eight alongside someone like Casemiro, rather than instead of.
Instead of fawning for a player like Amrabat for the entire summer, we should have been targeting a younger CDM with good mobility and athleticism. This player could then have played in Casemiro's place, or next to him in games where we wanted to be more defensively sound.
Casemiro also needed to be played in a manner which suits his game, not as the almost lone deep-lying playmaker he's been deployed as many times this year. He's played his best football next to Eriksen, who provides the intelligence and ability on the ball from deep which compliment him. Now Eriksen is nowhere near the physical level required to play CM at the top level, but transitioning from him to Mount (while losing Fred) is partially why our midfield has destabilised. The signing of Mount didn't help Casemiro, nor did it provide a good balance to Bruno Fernandes.
If we make the signing of Amrabat a permanent one - which seems the plan as why else would you spend £8.5 million on a loan fee for someone like him? - that will bring the total invested in midfield reinforcements this summer to nearly £90 million (£30 million on Amrabat + £55 million on Mount, potentially rising to £60 million). Yet none of that money has actually been spent on a player who compliments Casemiro. Which makes the original outlay spent on him look much worse than it could have been, with a more deliberate and well-thought-out plan.
That being said, a player with Casemiro's experience has to take responsibility for his performances this season, which have been abysmal and painfully naive at times. You shouldn't need the perfect conditions to deliver a good midfield performance at home against Galatasaray, as an example.
Continuing to play ninety minutes for Brazil every international break with thousands of miles of travel is also not helping things either. He went off injured in Brazil's first game during the last break, but played the second game. Came back here and couldn't play for three games as a result. Then goes off injured in his first game back at half-time, to then be ruled out for two months. So why did he play that second game for Brazil?
So there's some individual blame set against a backdrop of poor collective planning when assessing Casemiro's signing.
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