Manchester United's medical staff reportedly detected a back injury for Sofyan Amrabat during his medical with the 20-time English champions on transfer deadline day.
Following months of speculation, the Morocco international finally completed a move to Old Trafford on September 1, arriving on an initial loan deal from Fiorentina.
Man United will allegedly have the option to make the move permanent during next summer's transfer window for a fee in the region of £17.1m plus £4.3m in add-ons.
According to The Athletic, during his medical, it came to light that the 27-year-old was suffering with a minor back injury, but the club still decided to press ahead with a move.
The report claims that the issue is 'not serious', and he could be available to make his debut for the club in the Premier League clash with Brighton & Hove Albion on September 16.
Amrabat has not been involved for Fiorentina this season due to the speculation surrounding his future, but he has linked up with the Morocco squad for their September internationals.
The Athletic also claim that Man United were forced to pay twice as much for Amrabat's loan deal after Fiorentina were outraged by the English club's initial offer.
The report claims that Fiorentina had asked for £4.3m last week, but after the Red Devils only offered £2.5m, the Italian outfit said that the deal was no longer on the table.
Discussions ultimately resumed, with the Europa Conference League finalists now allegedly asking for £8.5m, which was paid by the 20-time English champions in their desperation to complete a deal.
Amrabat's squad number for Man United was confirmed on Tuesday, with the Moroccan set to sport the number four for his new club.
Speaking after Sunday's 3-1 defeat to Arsenal, Red Devils head coach Erik ten Hag explained why he was so keen to bring the midfielder to the club.
"It was already, from the start of the season, one of my wishes to get another [number] six, a holding midfielder, in the squad because through the season you need that depth there," Ten Hag told reporters.
"In that position we only had Casemiro who can play really well there. With others we have to make compromises but, with Sofyan Amrabat, we have another one.
"Also he can play alongside Casemiro because he can also play a little bit higher on the pitch. So it's very good to have him and I think he fits very good to Premier League football, to Champions League football. I think the demands are strong.
"He is very dynamic, he's very good in the duels. So we are pleased that we have him at United and I think he will contribute to our high targets we set."
Amrabat, as expected, has been named in Man United's squad for the group stage of the Champions League, but there is no room for Dutch midfielder Donny van de Beek.
