The former Real Madrid man saw his fortunes take a nosedive in the 2023-24 campaign, even though he was still a fundamental part of Erik ten Hag's Red Devils squad.
Casemiro made 32 appearances last season, notching five goals of his own and setting up three more, but the consensus was that the Brazilian failed to hit the same heights he did in 2022-23.
Casemiro was also forced to fill in at centre-back at times throughout the season due to Man United's defensive injury crisis, although he still ended the season with an FA Cup winners' medal around his neck.
However, the 32-year-old did not make the squad for the 2-1 victory over Manchester City in the final, and Sir Jim Ratcliffe is thought to be happy to do away with him as he prioritises a youth-driven rebuild.
Al-Ittihad 'begin discussions' over Casemiro move
Casemiro is still under contract at Old Trafford until 2026 with the option of an additional 12 months, but according to L'Equipe, Saudi titans Al-Ittihad have now begun discussions to prise him away from Old Trafford.
A transfer to the Middle East is thought to be Casemiro's only realistic escape route from the Theatre of Dreams this summer, especially when his wage packet - believed to be £300,000 a week - are taken into account.
Joining Al-Ittihad would see Casemiro reunite with former Real Madrid teammate Karim Benzema and compatriot Fabinho, while also linking up with another tough-tackling midfielder in N'Golo Kante.
However, Man United are believed to have slapped a £30m price tag on the head of Casemiro, and the door is not thought to be totally closed on the 32-year-old remaining at Old Trafford for the 2024-25 campaign.
If no interested party can stump up the Red Devils' rumoured asking price, Man United supposedly cannot afford to terminate Casemiro's contract, as they would have to award him an eight-figure payoff.
Casemiro boasts a respectable total of 12 goals and nine assists from 83 games in a Man United shirt, but he was not selected for the Brazil squad for the 2024 Copa America, where the Selecao lost on penalties to Uruguay in the quarter-finals.
Who could replace Casemiro at Man United?
While there are still many uncertainties surrounding the future of Casemiro, Man United have already been linked with a host of midfield enforcers capable of succeeding the five-time Champions League winner.
Paris Saint-Germain's Manuel Ugarte is rumoured to have emerged as a prime target, as the Uruguay international could prove cheaper than fellow targets Joshua Kimmich (Bayern Munich) and Joao Neves (Benfica).
Alternatively, the Red Devils could re-sign Sofyan Amrabat from Fiorentina on a permanent deal, although they would have to negotiate a fee with their Italian counterparts now that his loan - which included an option to buy clause - has expired.
However, Man United will reportedly need to shell out just £12.7m to reunite with the Moroccan, who would be a cut-price option for a team apparently starting the summer window with a budget of just £50m.