Sergio Ramos-Nicolas Otamendi
Sergio Ramos an dNicolas Otamendi have both been linked to Manchester UnitedGetty

Manchester United are hoping to add Real Madrid star Sergio Ramos and Valencia defender Nicolas Otamendi, according to the Spanish newspaper AS.

Louis van Gaal wants to strengthen his side's back four for the next season. The Red Devils are close to completing the signing of Matteo Darmian after Torino manager Giampiero Ventura confirmed the Italian is moving to Old Trafford.

Ramos has been strongly linked to United as Real look to sign their keeper David de Gea. The stopper has one year left on his contract with his current employers and wants to return to Madrid.

De Gea is keen on joining the 10-times European champions in the summer transfer window. However, the Mirror claims United are not willing to let their star player leave until Real pay a world record fee for the goalkeeper.

Former Real Madrid president Ramon Calderon has already admitted that Ramos will join the Premier League giants. The Spanish capital club had set their sights on replacing their centre-back with Otamendi.

The Argentine international is also on United's radar and is edging closer to completing a move to Old Trafford. In addition to this, he is a non-EU player and that will force Rafael Benitez to allow one of the non-EU players to leave the club.

This has forced Real to make an approach in re-signing their former player Ezequiel Garay as Ramos' replacement. The Zenit St Petersburg defender was at Santiago Bernabeu for three years, before joining Benfica in 2011.

Garay holds a European passport and a move for the 28-year-old will not force Real to let one of their players leave. The La Liga giants may only make an approach for him if Ramos joins United this summer.

Van Gaal has the services of Chris Smalling and Phil Jones as the first choice centre-backs in the squad. The England international duo recently signed new deals and despite that, the United manager wants Ramos and Otamendi to be his new central defenders for the next season.

A move for both Ramos and Otamendi will only bolster United's back four, but it will also force them to spend a large chunk of the transfer funds in securing the services of the La Liga defenders.