If the likes of the out-of-favour Luke Shaw depart in the New Year, the United manager may well attempt to seek the signature of Valencia's Carlos Soler, according to The Independent's Miguel Delaney.
Fellaini rejected a new contract offer from United in September and will be free to sign a pre-contract agreement with a foreign suitor in January.
There will not have been a huge increase in his wages given that the player turns 30 next week.
A report earlier this week in Marca suggested Los Che would consider selling Soler to raise vital funds, especially if they do not qualify for this season's Champions League.
GETTYJose Mourinho has enjoyed success before in the Champions League
Fellaini signed in 2013 on a four-year contract with the option on the club's side to trigger a further year which they did for this season. Fellaini signed for Everton in a deal worth £15 million, and he quickly established himself as a first-team regular.
He was seen as the on-pitch symbol of David Moyes' doomed ten months in charge.
He scored in the Europa League semi-final victory over Celta Vigo and also started in the 2-0 win over Ajax in the final.
After enduring a hard return to Old Trafford last season as the-then world's most expensive player, the 24-year-old as began this campaign in explosive fashion scoring twice and assisting three times in the opening four games.