Lukaku limped off against Arsenal last weekend with an ankle complaint and is recovering back in Belgium, where he was filmed moving freely in a medicine ball exercise on Thursday.

Those images suggest the 24-year-old's injury is not as bad as first feared, with Mourinho confirming the striker should be able to play against Chelsea in the FA Cup final on May 19.

"I don't know (how he is)," Mourinho said. "I just know that, of course, (he is) not (available) tomorrow. Apart from that, we need to wait for more scans, more time but not tomorrow."

Asked if there was a chance for the FA Cup final, Mourinho added: "Hope so. Looks positive."

Mourinho is also hopeful about last weekend's match-winner Fellaini staying at Old Trafford beyond the summer.

Contract talks with the 30-year-old midfielder have been at an impasse throughout the season, but the United boss still believes he will stay put amid interest from some European giants and the Chinese Super League.

"I am still positive," Mourinho said. "He's important.

"He's a player that I like but, again, especially for him, he has a different position in relation to other players with contract because other players with contract we can control their destiny in a different way.

"In Marouane's case, destiny is in his hands and he will decide what makes him happier. He knows that I want him to stay, he knows that the club wants him to stay. He has an offer from us and it's up to him now to (say) yes or no.

"I am still positive because I feel that he likes to be here, I feel that he likes the feeling of the manager trusting him and I think there is a good chance for him to stay. But if he leaves, so be it and be happy."

Fellaini looks set to be involved on Friday, when Eric Bailly may well be watching from afar.

The defender has been absent from the last two matchday squads but Mourinho explained that was due to the Ivory Coast's World Cup absence rather than any fitness concern.

"I try not to (make those emotional decisions), I try to be a good team manager and that means (being) a bit cold, a bit selfish," Mourinho said.

"But I'm not as bad as that and I still have space for a little bit of feelings so when I look to the other four central defenders fighting for a position in the World Cup, I am giving less to Eric."

That stance could also explain Daley Blind and Matteo Darmian's lack of game time, although they were on the periphery long before the World Cup was beyond their countries.

Their future is the subject of much speculation but Mourinho suggested he would like the defenders to stay.

"They are part of my plans," the United manager said. "I think when a player wants to go, if that's the case, and when the right offers arrive in the club, we study that because we always try to have the players happy.

"So, if happiness means for them to leave let's see what happens, but they are in my plans I don't want to sell, I want to keep."

- PA