Jose Mourinho has made no secret of the fact that he is in the market for a new centre half. Since the moment the season ended, reports of negotiations with Tottenham over Toby Alderweireld have been near constant.
At first, the Red Devils thought they could get the Belgian for around £45 million, but the fee now wanted by Daniel Levy is reportedly closer to £75 million, especially if Mourinho refuses to let Anthony Martial the other way.
The Manchester Evening News revealed on Tuesday that United have now moved on from Alderweireld and are pursuing new targets.
Whilst this may just be a ploy to make Levy play ball, here are the seven centre backs that the Red Devils are now considering as alternatives.
1 Raphael Varane
Current club: Real Madrid
Transfermarkt value: €70 million
Despite winning no league titles in the last five years, United remain one of the biggest clubs in the world with the pull to sign almost any player.
Targeting Raphael Varane, however, may seem a touch ambitious.
The elegant 25-year-old defender has nailed his place in Real Madrid's starting XI over the last couple of years, and provides an excellent compliment to Sergio Ramos in Los Blancos' backline.
Quick across the ground, composed on the ball, and strong in the air, Varane would be a dream signing for United.
It was actually Jose Mourinho that brought the Frenchman to the Bernabeu back in 2011, beating Sir Alex Ferguson to his signature, but a reunion seems a dream too far for United fans.
Settled at Real Madrid, having won three consecutive Champions Leagues, why would he leave, especially as Sergio Ramos ages?
2 Jerome Boateng
Current club: Bayern Munich
Transfermarkt value: €45 million
Another somewhat fanciful United target, but again, he would be an outstanding signing if he wanted to return to Manchester.
It's hard to believe that Manchester City let the classy defender slip through their fingers, but their loss has been Bayern Munich's gain.
Boateng did hint back in April that he may be exploring new opportunities, having won everything with the German champions. Whether or not this was merely posturing for an improved contract remains to be seen.
If Boateng did in fact decide he wanted to leave, Old Trafford would seem a good location for him, as a club big enough to match his ambition... and his price.
Has dropped hints that he may be willing to try something new, but whether he'd actually go through with it, and whether Bayern would let him, is a totally different matter.
3 Kalidou Koulibaly
Current club: Napoli
Transfermarkt value: €60 million
One of the Napoli stars to announce themselves on the world scene this season. His outstanding performances as they ran Juventus so close for the title made people really sit up and take notice.
Currently in Russia for the World Cup with Senegal, Koulibaly's future probably won't be sorted for another few weeks at least.
He has shown himself to be remarkably comfortable on the ball in Maurizio Sarri's system at Napoli, and would present a massive upgrade on the likes of Chris Smalling and Phil Jones in this respect.
A host of clubs have expressed an interest and a bidding war could ensue after the World Cup, but United do have the funds to out-muscle most in the market.
If Napoli play ball, Koulibaly would probably favour a move to United over most others.
4 Milan Skriniar
Current club: Inter Milan
Transfermarkt value: €45 million
The 23-year-old Slovakian is less of a household name than some of the others on this list, but played every single game in Serie A for Inter Milan this season.
Strong and good on the ball, having played in midfield for his country, Skriniar could be a slightly cheaper alternative to some of the others. Only slightly though, as he would cost more than £50 million.
As Slovakia failed to qualify for the World Cup, this is a move that could potentially be pushed through fairly quickly if United decide to pursue it.
Would definitely fancy a move to United, whether or not they decide to go for him over other targets, though, remains to be seen. Could be a backup option that they go back to later in the summer.
5 Caglar Soyuncu
Current club: Freiburg
Transfermarkt value: €18 million
Linked heavily with a £35 million move to Arsenal, United could potentially hijack the Gunners' move for the Freiburg defender.
Soyuncu is just 22 and it would be a big gamble to pay that kind of fee for a young player.
The Turkish international has shown promise in the Bundesliga, but slight in frame and not particularly great on the ball, he doesn't seem to be a great fit for Mourinho's United.
He is an improving young player, but the jump up may be a little too much for now.
With Arsenal lurking this would probably have to happen soon, and with United's interest in Alderweireld likely to linger in the background, this move seems unlikely.
6 Alessio Romagnoli
Current club: AC Milan
Transfermarkt value: €40 million
At just 23 years old, Alessio Romagnoli has racked up an impressive 111 appearances for AC Milan since signing three years ago.
A modern centre half standing at six foot two, he possesses a cultured left foot. Saying this, he is also an excellent one-on-one defender in the traditional sense.
United could do with a better left-footed option than Daley Blind or Marcos Rojo, and Romagnoli would represent a significant upgrade.
This feels like a deal that is relatively quiet right now, but could pick up pace as the summer goes on - one to watch.
All seems a good fit, but could hinge on Milan's reluctance to let their star defender go. Another that would cost north of £50 million.
7 Jose Gimenez
Current club: Atletico Madrid
Transfermarkt value: €45 million
Has been back in favour at Atletico since the turn of the year, putting in some excellent performances in one of the most notoriously stingy defences in the world.
A big, aggressive, mobile defender, Jose Gimenez is a perfect Jose Mourinho player. He can thrive on the front foot or when his team are backs against the wall.
In late 2017, the notion of Gimenez leaving for United would have probably been welcomed by both sides, but in the second half of the season the 23-year-old proved himself to Diego Simeone as someone he could now rely on, without the silly fouls of yesteryear.
Whether Atletico may be tempted to cash in on a player that they plucked from Danubio in his native Uruguay for under £1 million five years ago remains to be seen.
If Atletico play ball, this would be an excellent fit for both United and Gimenez.
Listen to the RealSport football writers discuss Group E in Kremlins in the Basement: RealSport’s daily World Cup podcast.
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