Manchester United have turned their attention to AS Monaco defender Fabinho as their preferred choice for the right-back role. Getty

Manchester United have reportedly made an offer to sign AS Monaco right-back Fabinho during the summer transfer window.

According to French newspaper L'equipe, the Red Devils have approached the Ligue 1 club to check the possibility of signing the defender with a £10m ($15.8m) offer as Louis van Gaal looks to bolster his defence.

The Dutch manager has made signing a right sided defender a priority this summer as he looks to bring in a player to replace Rafael, who will be allowed to leave the club and challenge Antonio Valencia, currently playing in the right-back position.

Fabinho, who spent the last two seasons on loan at Monaco from Portuguese club Rio Ave, was signed on a permanent deal by the French club last month. The fee for the Brazilian, who made 53 appearances in all competitions last season, was said to be in the region of £4.3m ($6.8m).

Despite only making his deal permanent recently, it is believed that the Principality club are ready to let the defender leave, only if interested clubs meet their valuation.

According to the Daily Mail, United's initial offer of £10m has been rejected by the French club and they are demanding a fee closer to the £20m mark to part with the Brazilian international. Fabinho is currently with the national team in Chile for the Copa America, which got underway on 11 June.

The 20-times English champions have been linked with moves for various right-backs in recent weeks with Dani Alves and Nathaniel Clyne being the most frequently mentioned names. The former has since committed his future to Barcelona, while the Southampton defender is also a target for Liverpool.