Having considered a move for the Portugal international over the summer, the 25-year-old was made the Old Trafford giants' chief target this month.

United and Sporting have been at loggerheads over Fernandes' valuation, but it is understood a deal to take the midfielder to England is now close.

Final figures and personal terms remain, but a fee of 55 million euros ($A90 million) and a further 10 million euros ($A16 million) in add-ons are believed to have been settled on.

Those add-ons are understood to be based on appearances and Champions League qualification, while it would take a hugely successful stint at Old Trafford to trigger a further 15 million euros ($A24 million).

A four-and-a-half year deal is on the table for Fernandes, for whom Sporting are believed to have initially demanded 80 million euros ($A130 million) up front.

The move is subject to a medical but United are confident of getting the deal over the line - a boost for a side left light in midfield by the departures of Marouane Fellaini and Ander Herrera.

Ole Gunnar Solskjaer is understood to have wanted to bring in a central midfielder over the summer, while injuries to Paul Pogba and Scott McTominay have compounded matters.

But United, who have tracked Fernandes since 2015, now appear to be getting their man - a player Solskjaer had been coy about ahead of Wednesday's Carabao Cup semi-final against Manchester City.

"I haven't got any updates for you on transfers," Solskjaer said with a laugh on Tuesday morning. "I think it was a waste (of a question) - I gave you the option (not to ask it)."

United are looking for an attacker as well as a midfielder so Alexis Sanchez would have been a welcome option at this point, despite his struggles since his high-profile switch from Arsenal in January 2018.

And while the Old Trafford giants did not include a recall clause in his season-long loan deal to Inter Milan, Solskjaer expects him to have a future at the club when he returns in the summer.

"It's very hard because the clubs don't want to lose their best players. Alexis will come back in the summer and prove you all wrong."

Australian Associated Press