Fiorentina midfielder Sofyan Amrabat reportedly saw a problem flagged up during his Manchester United medical, but still completed the transfer on loan with option to buy.
The deal was done so late on deadline day that he had no time to undergo tests before the paperwork was signed and delivered.
As the Premier League giants could not afford to make the €35m move stick, they have taken Amrabat on loan for €10m with an option to buy for a further €20m plus €5m in add-ons.
According to The Athletic, Manchester United spotted a minor back injury during the medical tests, but it was not enough to stall the move.
Indeed, he will also still be attending international duty with Morocco.
It is a recurring issue and one that saw him play on using pain-killing injections during the 2022 World Cup in Qatar.
The midfielder has chosen the Number 4 jersey at Old Trafford.