Ole Gunnar Solskjaer is desperate to add depth in midfield ahead of the new campaign.
Marouane Fellaini and Ander Herrera’s departures have left options limited in the middle of the park, while Paul Pogba continues to be linked with an exit.
Fernandes has emerged as Manchester United’s No.1 target after he scored a stunning 32 goals for Sporting last season.
The Portuguese has a release clause of €80m (£72m).
But United chiefs are confident of landing him for significantly less.
And according to The Independent, the club are working on an appropriate offer.
Reports earlier this month suggested United had put a deal for Fernandes on ice until they brought in a new centre-back.
Harry Maguire’s move from Leicester appears to be edging closer and attention can now be turned to the midfield.
“Sporting have been informed that an offer will come in from Manchester United this week.”
Journalist Duncan Castles
Sean Longstaff is also a target but United have been put off by Newcastle’s £50m asking price.
Fernandes is believed to be keen on a switch to Old Trafford and journalist Duncan Castles has revealed that the 24-year-old’s agent has told Sporting about the imminent bid.
“It’s welcome [news] to Sporting, whether it turns into the transfer that a lot of Manchester United fans are hoping for we will find out,” he said on The Transfer Window podcast.
“Sporting have been informed by Bruno Fernandes’ agent, his brother-in-law Miguel Pinho, that an offer will come in from Manchester United this week.”
And Solskjaer hinted last week that United are struggling to bring in players due to selling clubs’ asking prices.
“We have been linked with so many players,” he said.
“I’m sure you don’t believe every single player that we’ve been linked with, but I think that Manchester United sometimes have, because of the wealth, maybe we have had to pay more, a bigger premium to get players in, and that’s just the world we live in.
“And we’ve taken our time. We’re not going to overpay, but we have to get the right people in, the right players.”