Valencia said that an initial medical examination had revealed a problem in the player's left knee and that they would need 15 to 20 days to carry out more tests in to order to decide whether the move could go ahead.

The club said Kluivert had undergone arthroscopic surgery at the end of the season and that the after-effects of the operation meant they were unable to assess his knee.

But the 28-year-old, who was due to sign a three-year deal with the club after being released by Newcastle United last week said he was certain that the deal would go through.

"I know that it's nothing serious and that when I return it will be all sorted out," he was quoted as saying by sports daily Marca.

"During the season at Newcastle I was suffering from some pain. I could play, but three days after the league finished I was operated on. A lot of players have this sort of thing done at the end of the season and it is only to clean up the knee.

"I want to come back and I'm very keen on the move. I still want to play football and I can do that in Valencia. I've spoken to the people at Valencia and we've got an agreement and when I come back it will all be fine."