Sir Jim Ratcliffe reportedly questioned Manchester United's purchase of Casemiro from Real Madrid when he visited the club's Carrington training complex in March.
The 71-year-old's arrival as a minority shareholder is expected to be confirmed in the near future, with the final stages of the agreement being discussed on Thursday night.
Ratcliffe is set to take over football operations at Old Trafford, with the British billionaire said to be desperate to address a department which he believes is failing.
Man United's transfer policy in recent years has been widely criticised, and according to The Athletic, Ratcliffe questioned the club's big-money move for Casemiro.
The report, meanwhile, also claims that various staff members believed that the Red Devils should have actively targeted Declan Rice in the summer of 2022 rather than moving on to Casemiro when a deal for Barcelona midfielder Frenkie de Jong broke down.
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Man United spent much of Erik ten Hag's first window as head coach pursuing De Jong, but the Netherlands international said on at least two occasions that he was not interested in a move.
The Red Devils instead spent £60m on Casemiro, with the Brazil captain being handed a four-year contract, while there is also the option to extend the deal until June 2027.
The midfielder has made 63 appearances during his time at Old Trafford, scoring 11 goals and registering seven assists in the process.
Casemiro has four goals and one assist in 12 appearances this season, but he has been out since the start of November with a hamstring problem.
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The Brazilian is in line to return in the middle of January, and he is expected to stay with Man United next month despite the recent speculation surrounding his future.
A departure next summer is thought to be a possibility, though, with a number of Saudi Arabian clubs said to be keen on his signature.
Rice ultimately stayed at West Ham United for the 2022-23 campaign before completing a big-money move to Arsenal during the recent market.
The England international has been a key player for the Gunners this season, contributing three goals and two assists in 25 appearances in all competitions.
Man United were also thought to be keen on signing Jude Bellingham when it became clear that the midfielder would be leaving Borussia Dortmund, but he ultimately made the move to Real Madrid.
Matt Law
