United are badly in need of midfield reinforcements due to the absence of Paul Pogba and Scott McTominay through injury, whilst Pogba's future at the club beyond the end of the season is very much in doubt.
Fernandes will cost the Red Devils an initial 55 million euros (£47 million, $61 million) with up to 25 million euros more in performance-related add-ons.
However, United know to their cost that even such a huge fee is no guarantee of success after seven years of decline since former manager Alex Ferguson retired in 2013, despite splashing over £1 billion on transfers.
So, who is Fernandes and can he help lead a revival of United's fortunes?
One area where Fernandes clearly fits United's needs is a goal threat with top scorer Marcus Rashford sidelined by a back injury to compound the absence of Pogba and McTominay.
He scored 63 times in 137 appearances for Sporting since returning to his homeland in 2017 after spells with Novara, Udinese and Sampdoria in Italy.
Of those 47 have come in the last season-and-a-half as he has blossomed into a potent threat, earning comparisons with Chelsea manager Frank Lampard - the top scoring midfielder in Premier League history.
"He is a complete player, and if you ask me to compare Bruno with a player, I will say Frank Lampard," former Sporting manager Carlos Carvalhal told talkSPORT.
Fernandes's ability to shoot from range could be the key to unlocking deep-lying defences that Solskjaer's men have struggled to break down this season.
Man United close to completing Bruno Fernandes deal
Moreover, he has also been a creative force during his time at Sporting, providing 42 assists in total and creating the most chances in the Portuguese league for the past two seasons.
Unlike many products from the Portuguese league, Fernandes is making the move to England in the prime of his career rather than as a precocious youngster.
One of those young talents went onto become one of United's best ever players when Cristiano Ronaldo made the move from Lisbon to Manchester in 2003 as an 18-year-old.
Portuguese football expert Tom Kundert believes the timing on Fernandes's transfer means he is well-equipped to make the step up to the Premier League.
"In 25 years watching Sporting live every other week Bruno Fernandes is undoubtedly the best player I've seen in the green and white," said Kundert.
"Yes, Sporting had (Luis) Figo and Ronaldo, but they weren't the players at (Jose) Alvalade they'd become. Fernandes is the finished article. Ripe for a bigger challenge."
A lack of leadership has been highlighted as one of United's problems in recent seasons. Harry Maguire was recently handed the captaincy after less than six months at the club.
Fernandes was forced to grow up fast in Lisbon, captaining Sporting through a institutional crisis when a group of angry fans attacked some players at the club's training ground in May 2018.
Many of Sporting's stars choose to rescind their contracts and leave following the incident, but Fernandes stayed and signed a new contract before going onto score 32 goals last season.
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That experience could be important in helping lead United out of their own toxic period. Executive vice-chairman Ed Woodward's house was targeted with flares and graffiti on Tuesday.
With United languishing fifth in the Premier League, six points off the top four, animosity towards Woodward and the club's American owners, the Glazer family, has risen among the club's fanbase in recent weeks.
They are now banking on another lavish purchase in Fernandes to quieten that discontent.
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