Rio Ferdinand has advised Manchester United to move for Saul Niguez, Thomas Partey and Wilfred Ndidi in the summer transfer window.
Ole Gunnar Solskjaer's rebuilding job at Old Trafford is expected to continue when the market reopens later in the year.
The Norwegian has already added Daniel James, Aaron Wan-Bissaka, Harry Maguire and Bruno Fernandes to his ranks, while also securing Odion Ighalo's services on loan from Shanghai Shenhua.
However, the Red Devils are still considered to be one or two players short of challenging the elite on domestic and European fronts once again, after enduring a mixed 2019-20 campaign.
United were sat fifth in the Premier League standings before the coronavirus-enforced break in the season, three points adrift of fourth-placed Chelsea in the race for Champions League qualification.
An 11-match unbeaten run saw Solskjaer's men climb back up the table and reach the latter stages of both the FA Cup and Europa League, with Fernandes and Ighalo inspiring an impressive turnaround in fortunes.
Despite United's improved form since the winter break, a number of top players continue to be linked with moves to Old Trafford, and Ferdinand believes the midfield is still in need of some surgery.
It has been reported that Aston Villa's Jack Grealish and Leicester ace James Maddison are United's two top targets, but a club legend would like to see two Atletico Madrid stars and another key performer at the King Power Stadium targeted.
"I’d maybe go get Partey from Atletico Madrid or Ndidi from Leicester," Ferdinand said on The Beautiful Game podcast.
"I like Saul Niguez. He’s a very, very good player in midfield."
The ex-United defender went on to express his belief that Solskjaer could also do with an extra centre-back, naming a Norwich talisman and Napoli enforcer as possible options.
Ferdinand added: "And then a centre-back, they still need a centre-back.
"Whether you go for a young one like a Ben Godfrey or someone like [Kalidou] Koulibaly. I don’t know, it’s difficult."
United have also been tipped to make a formal approach for Borussia Dortmund's Jadon Sancho, but executive vice-chairman Ed Woodward has warned that it "won't be business as usual" for the club due to the potential financial repercussions of the Covid-19 pandemic.