The 32-year-old, who has been a major part of the recovery inspired by new manager Kevin Keegan in recent weeks, has been playing with an injury which it is understood could require surgery at the end of the campaign.

He is expected to be available for the club's final two Barclays Premier League fixtures, against Chelsea on Monday and Everton on the final day of the season.

seen enough

However, Socceroos coach Pim Verbeek has resigned himself to being without Viduka for the qualifiers against Iraq twice, Qatar and China in June as they attempt to secure their place in the 2010 finals in South Africa.

That would come as a blow to Verbeek, who admits Viduka remains a key part of his plans.

He said: "Nobody can do the same as Mark Viduka. I have seen enough games in England and Europe - he is special. You don't see players like him very often. He is so important for the team."