The FA Cup finalists have achieved their best-ever points record in the Premier League post-Sir Alex Ferguson but have fallen considerably short in the title race. United are currently 16 points adrift of champions Manchester City after 34 games.
Carrick has already announced his retirement from professional football and will securing a coaching role for next season, while Fellaini has yet to put pen on new contract.
The duo have hardly played this season, racking up a combined 543 minutes of Premier League football under Mourinho, but their departures will need to be replaced as they’ll have very little cover in the engine room in case of injury.
Nevertheless, the likes of Paul Pogba, Nemanja Matic and Ander Herrera delivered an impressive midfield showing as United beat Tottenham Hotspur in the FA Cup semi-finals, booking their place in the final against Chelsea next month. Mourinho will be keen to beat his former employers.
Their immediate focus will be on securing second place behind Manchester City, however, which they can do with a win over Arsenal next weekend. The Red Devils will seal the runners-up spot with seven points from their remaining four matches.