Ryan Giggs says Ole Gunnar Solskjaer's Manchester United squad is "a couple more midfielders" short ahead of the start of the new 2019/20 season.
Paul Pogba has been linked with a move to Real Madrid as well as Juventus this summer, with the Frenchman admitting that he wants a "new challenge".
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Los Blancos tabled a £27.6m bid (plus James Rodriguez) for the World Cup winner, prior to the transfer window closing for Premier League and Sky Bet Championship clubs on August 8.
Meanwhile, Ander Herrera moved to Paris Saint-Germain after his contract came to an end last term, Marouane Fellaini also joined Chinese Super League side Shandong Luneng Taishan in January.
Nemanja Matic, Juan Mata, Scott McTominay, Fred, Tahith Chong and Andreas Pereira make up Solskjaer's remaining options in that position.
Amid fear that Pogba could potentially yet leave Old Trafford with the European transfer window closing on September 2, Giggs has warned that United need further back-up in centre midfield.
"I think we need a couple more midfielders," United's record appearance holder told ESPN.
"If Paul Pogba goes we talk about culture change, but obviously you need quality.
"You might not like it but come Sunday if Paul Pogba isn't in that midfield or the week after, and we've got the midfielders that we've got at our club, then we're short.
"That's the problem."
The arrivals of Harry Maguire, Aaron Wan-Bissaka and Daniel James have bolstered Solskjaer's squad in defensive and wide areas.
But Romelu Lukaku was not replaced before the transfer deadline and departed to Inter Milan in a £73m deal.
Instead, Solskjaer has made it clear that he wishes to develop and have faith in young forward players Mason Greenwood and Marcus Rashford, ahead of the new season.
United begin their top flight campaign against Chelsea at Old Trafford on Sunday August 11; live on Sky Sports Premier League from 4pm, kick-off 4:30pm.