I think some of you miss the whole picture.
The club and his coach do need to renew his contract so that the club would be in a position to sell him later, say 15-25 millions next year.
Fellaini renews his contract: player in the squad + option to sell him in the future >>> You don't spend money this summer to replace him and can earn money 15-25 later. Fellaini is a decent squad player after all.
Fellaini doesn't renew: you have to acquire a new player this summer to replace him at a high price because you're United >>> You will spend 20-30m to have the equivalent of Fellaini (i.e. a squad player) this summer
Last but not least, Fellaini will play a lot this season to feel the 'confidence' of the club and consequently to be more inclined to renew his contract... Mourinho is asked to consider him to help the club renewing his contract.
From the club standpoint, Fellaini has to be viewed as an ASSET and the club just wants to maximize the return on his investment.
Mourinho also has his own agenda
- Fellaini renews his contract: Mou would be in a position to spend X millions for 4 players next summer for example
- Fellaini doesn't renew: Mou would have to spend the same amount of money X millions for 5 players then, which would make his plans more challenging
Last but not least, Mou knows Fellaini: so if the latter is on the bench, Fellaini won't be a burden within the squad and the situation will be "under control" from a managerial standpoint too.
Of course, it doesn't make sense to offer him a VERY crazy salary package.