On the back of his performances for Morocco at the 2022 World Cup, Amrabat attracted widespread interest in January and the summer of last year.
United ultimately won the race to sign the Fiorentina midfielder, initially on a season-long loan deal with the option of making it permanent.
Given the prolonged chase for the 27-year-old's signature, the assumption was that United would push through a transfer at the conclusion of the current campaign.
However, Amrabat has failed to replicate his form for his country at Old Trafford, being restricted to 13 starts and 10 substitute outings in all competitions.
Amrabat out of Man United plans?
With minority owner Sir Jim Ratcliffe in charge of football operations, United are expected to move in a fresh direction during the next transfer window.
According to transfer expert Fabrizio Romano, that will involve Amrabat returning to parent club Fiorentina, rather than be kept in the first-team ranks at United.
Romano says that club officials have already made the decision not to activate the €25m option that is present in their agreement with the Serie A outfit.
Furthermore, it is claimed that AC Milan are among "many clubs" who are monitoring the situation ahead of making their own move for his signature.
Since 2019-20, Amrabat has played the bulk of his football in Italy, making a total of 117 appearances in the top flight for Hellas Verona and Fiorentina.
Is a move to AC Milan realistic?
Fiorentina would have been hoping that United exercise their option to sign Amrabat given that his contract is due to expire in 2025.
Realistically, I Viola will not be able to generate that fee from another club, while the player is unlikely to have any interest in a renewal at this stage.
Milan already have a range of options for their engine room, with the younger Ismael Bennacer and Yacine Adli their current defensive-minded choices.
However, neither of those players have made more than 15 starts in Serie A this season, suggesting that Stefano Pioli may be in the market for reinforcements.