Louis van Gaal, the Manchester United manager, has intimated that he would be interested in signing Victor Valdes once the goalkeeper completes his rehabilitation from the anterior cruciate ligament injury which has kept him out since March.

It was confirmed on Thursday that Valdes, a six-time league winner with Barcelona, is being allowed to use the Old Trafford club's training facilities as he continues his return to fitness. The 32-year-old - who is a free agent after leaving Barcelona at the end of last season - will join in with first-team training once he has recovered from the injury.

When asked whether he would consider signing the Spaniard if he returns to full fitness, Van Gaal was coy. "Manchester United has always their eyes open," he said.

The Dutchman has seen plenty of the goalkeeper already, having given Valdes his debut in 2002 after the coach returned to the Camp Nou to take charge for a second time. The Spaniard became first-choice under Van Gaal and remained so until the Dutchman decided to left the club during the following summer.

Valdes had been linked with a move to Liverpool, whose goalkeeper Simon Mignolet has endured a series of underwhelming performances so far this season. However, Van Gaal, whose goalkeeping coach Frans Hoek also worked with Valdes at Barcelona, has since offered the three-time Champions League winner the chance to recover from injury at his club's training base in Carrington.

The United manager will tomorrow also have a chance to become reacquainted with another former Camp Nou colleague, Jose Mourinho. The Portuguese will lead his unbeaten Chelsea side to Old Trafford to take on his former mentor, with Van Gaal having appointed Mourinho to his coaching staff at Barcelona 17 years ago. They spent three years alongside one another, winning two Primera Division titles and the Copa del Rey.

Van Gaal yesterday played down his role in the development of the Portuguese - who has since collected 20 trophies as a manager. "He talks about Louis van Gaal and also [another former Barcelona manager] Bobby Robson, and I appreciate that, but you always do it by yourself."

Mourinho appears to have developed a habit of engaging his coaching rivals in mind games all on his own, with the Chelsea manager having this week sent out conflicting messages concerning the fitness of striker Diego Costa. The Spain internationalist missed out against Maribor during the week due to a thigh injury but Van Gaal expects him to start at Old Trafford tomorrow.

"I think he [Mourinho] shall play with Costa when he can because he wants to win," the Dutchman added of a player who has scored nine goals this season. "He's in good shape, but I read he was ill yesterday."