Sergio Ramos
Sergio Ramos has been linked with a move to Old Trafford in recent weeksGetty

Real Madrid right-back Dani Carvajal says he cannot imagine Manchester United target Sergio Ramos "in the shirt of another club" but backs Iker Casillas's potential move to Porto should the Los Blancos captain believe "it's in his best interest".

Ramos has been linked with a summer move to Old Trafford in recent weeks since AS broke the story in June that the Spain international wanted to quit the Santiago Bernabeu even though he still has two years remaining on his contract.

The Telegraph recently reported that having had an initial£32m bid for Ramos rejected, United have told the Spanish giants they will not sell goalkeeper David de Gea to them unless they are allowed to sign the defender.

And while Ramos later denied "being in negotiations" with another club, Carvajal has now warned United the defender's departure from the Santiago Bernabeu is unlikely.

Asked whether he believes the centre-back will leave the club this summer, he replied, as quoted by AS: 'I don't know. All I do know is that he is a teammate of ours and a cornerstone of Real Madrid, and no one can imagine him in the shirt of another club."

Meanwhile, Spanish TV station RTVE reported on 6 July that Casillas has decided to put an end to his spell at Real Madrid to join Porto, with his agent later confirming the 'keeper "is enthusiastic about the possibility of going" to the Portuguese side.

And asked about that, Carvajal said: ''I reiterate that I don't want to get involved in this subject matter.

"This is a question for Iker to answer. I have an exceptional relationship with Casillas and if this is his decision, then I feel it's in his best interest."