Manchester United manager Louis van Gaal has insisted that goalkeeper David de Gea's number one position is safe by claiming that Victor Valdes has joined the club as "number two".

The former Barcelona shot-stopper has signed an 18-month deal, with the option of a further year, after joining the club in October to work on his rehabilitation from a knee injury.

Valdes's arrival has raised questions over De Gea's long-term future, amid reports that Real Madrid are interested in signing the Spaniard.

However, Van Gaal has made it clear that "impressive" Valdes will not be thrown into the first team.

"I am delighted Victor has signed for the club," Van Gaal told the club's official website. "Victor is a very experienced goalkeeper and his record speaks for itself. I have said on many occasions that Manchester United will always be interested in the best players.

"Victor has remained very professional throughout his rehabilitation from injury and has been very impressive during his training sessions with the first team over the past weeks. He joins the club as the number two goalkeeper and is a great addition to the first team."

Van Gaal gave Valdes his first senior start during their time together at Camp Nou.