Manchester United manager Ole Gunnar Solskjaer will be tasked with improving the Red Devils squad ahead of the new Premier League season.
The Red Devils finished in second place in the Premier League table last term but Manchester United are currently in sixth position in the top flight.
Solskjaer’s side are two points behind fourth-placed Arsenal but are involved in a competitive race to secure the final two top four positions.
Manchester United slumped to a 3-0 loss to La Liga giants FC Barcelona in the second leg of their Champions League quarter-final on Tuesday night.
The Red Devils could conceivably finish the season outside the top four and without a trophy for the second successive season.
Solskjaer is likely to require new players in the summer to help overhaul his Red Devils squad.
And former Manchester United midfielder Hargreaves believes that Solskjaer needs four new signings in the summer transfer window.
“I think they need four [signings] this summer,” Hargreaves told BT Sport.
“I think recruitment is going to be so important for Manchester United.
“[They need a] director of football, Ole Gunnar Solskjaer is going to need that help.
“For me it showed [against Barcelona] they need a defensive midfield player in that position. Fred played there, he’s a ball player.
“In three moments in the game where he could win a challenge or stop someone, he just didn’t do that.
“So I think he’s an eight like [Paul] Pogba, I thought [Scott] McTominay was terrific.
“Centre back, central midfield player is going to be so important, and a right winger.
“I think they’ve got great potential but the recruitment this summer has to be spot on.”
Manchester United will return to Premier League action with a difficult clash against Everton at Goodison Park on Sunday afternoon.
The Red Devils haven’t won the Premier League title since 2013 when Sir Alex Ferguson led Manchester United to title glory for the final time in his reign.
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