Manchester United Transfer News: Latest Rumours on Alex Sandro

Manchester United have reportedly "already approached" Juventus left-back Alex Sandro, per Duncan Castles of the Sunday Times.

Castles has named Sandro and Barcelona centre-back Samuel Umtiti as prime transfer targets for United manager Jose Mourinho. The Old Trafford chief wants to overhaul his team's defence this summer so he can "deploy more aggressive tactics against stronger opposition."

United have been criticised at times this season for a negative approach in big matches. The Red Devils were particularly shy about going forward during a 0-0 draw against Liverpool at Anfield in the Premier League, along with a 2-1 defeat at home to would-be champions Manchester City.

Mourinho perhaps thinks he can't commit men forward because a shaky defence needs more protection, with Castles noting the 55-year-old "believes the club's progress on domestic and European fronts has been limited by the quality of its defenders and is considering upgrades."

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Sandro makes sense as an upgrade because he would instantly improve United's talent at left-back. It's a position Mourinho has struggled to fill during nearly two seasons in charge of the Reds.

Daley Blind and Matteo Darmian both played out of position there last season, while veteran Ashley Young has been given the nod for most of this campaign. Young is a former winger who is now 32, making adding a natural left-back an obvious priority.

It's a need boosted by Mourinho's uneasy relationship with Luke Shaw. The pair reportedly had a heated confrontation after Mourinho substituted Shaw at halftime of United's 2-0 win over Brighton & Hove Albion in the FA Cup quarter-final, per the Daily Mail's Chris Wheeler.

Mourinho publicly criticised Shaw after the game, prompting a source close to the player to brand the manager's treatment as "disgusting," per Kaveh Solhekol of Sky Sports News.

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If Mourinho does decide to move on completely from Shaw this summer, he won't find a better replacement than Sandro. The Brazil international is an imposing athlete blessed with terrific recovery pace and impressive aerial power.

Aside from his defensive nous, Sandro is a relentless outlet going forward. His runs on the flank are direct, while his natural flair makes Sandro adept in possession.

Still just 27, he also has his peak years ahead of him. Putting the Juve man next to pacy and powerful centre-back Eric Bailly would go a long way to giving United the superior athleticism Mourinho covets in defence.

Recent rumours have suggested the Red Devils could pull off a deal, with Calciomercato (h/t Richard Fay of the Manchester Evening News) saying Juve must sell a key player because of financial pressure.

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Manchester Evening News writer Samuel Luckhurst has also dubbed Sandro as "Mourinho's preferred option."

Landing one of the best defenders in Europe would make a statement about United's commitment to building a back four capable of carrying the club to next season's title.