Ole Gunnar Solskjaer is set to spend big when the window reopens as he looks to overhaul his uninspiring squad.
Top on his list of priorities will be a centre-back, a position that Manchester United have needed to strengthen for quite some time.
Jose Mourinho failed with moves for Maguire, Toby Alderweireld, Diego Godin and Milan Skriniar last year before his toxic tenure came to a bitter end in December.
According to ESPN, United will return for Maguire this summer and the England international is a top target alongside Koulibaly as they look to bolster the heart of their defence.
It will come as music to the ears of supporters, who have watched their side leak 52 goals this season in the Premier League.
To put that into perspective, that’s four more than 14th placed Newcastle with still one match to play.
Manchester United are also believed to be out of the running for highly-rated Matthijs de Ligt.
The decision was made by the club ahead of the Champions League semi-final because of concerns about his weight.
De Ligt is the captain of Ajax at just 19 years old and gave his side the lead before their monumental collapse against Tottenham in Amsterdam on Wednesday night.
Barcelona are now set to make the most of their concerns and pounce and are keen to tie up a deal for the Dutch international.
Speaking at half-time of the rollercoaster game at the Johan Cruyff Arena, Mourinho heaped praise on the shoulders of De Ligt in the beIN SPORTS studio.
“In a funny way, I only believe De Ligt is 19 years old when I look at his face,” he said.
“I think he has fantastic maturity. I think he must be very, very intelligent. I think the kid is fantastic.”
Ajax CEO Edwin Van der Sar confirmed after the last-gasp defeat that he believes it will be one of De Ligt’s last games in an Ajax shirt.
“I think these will be De Ligt’s final games with Ajax,” he told Sky Italia.
“But I hope he goes out on a high. He’s been here since he was a child and will end up at a big club.
“I think he’ll go to England or Spain.”