The Belgian's current deal expires at the end of the season, and the Belgium international does not know if he will remain with Jose Mourinho's side.
Per HUMO (h/t Richard Cooke at Sky Sports) he said: "Honestly, I do not know.I have something in my head but I cannot tell you. This is my tenth season in England. Except for the very first at Manchester, I only knew good times.
"I'm still here. If Manchester did not want me anymore, they would have said that for a long time. They made a proposal, probably one will follow. Whether I will accept it I do not know. You cannot arrange something like that in a jiffy."
Fellaini is not a regular at United under Mourinho, but he is effective when he does feature, as shown by WhoScored.com:
Per Cooke, Fellaini also revealed he has discussed his future with Mourinho: "We talked about it. The coach is someone who respects the decisions of his players."
Although Fellaini has started just three times in the Premier League this season, United would still be loath to see him walk away for free when his contract expires at the end of the campaign.
Samuel Luckhurst at the Manchester Evening News said Fellaini could be one of several players to leave Old Trafford next year:
Fellaini is sidelined with a knee injury and is expected to be out until January, according to Mark Critchley at The Independent.
Turkish Football @Turkish_Futbol1
LATEST: Fellaini's representatives have held several rounds of talks with Beşiktaş & Galatasaray. Four-year deal, €4-5m per-season are the numbers were talking. Would have been a done deal but #MUFC boss Mourinho is throwing a spanner in the works. Does NOT want to lose him
Fellaini's reluctance to sign a new deal is understandable. At 30, this may be his last big contract, and he may also be seeking assurances over his playing time.