The football world closed ranks round Alan Stubbs last night as the Celtic defender faced up to what could be the biggest match of his life. Stubbs confirmed that he will undergo an exploratory operation today after a random drugs test revealed he was suffering from an unnamed illness.

Such were the results of the tests that drug abuse or performance-enhancing substances were discounted immediately. And while neither player nor club would elaborate, it was deemed serious enough for both to appeal for privacy.

The problem arose when Stubbs took a random drugs test following the Scottish Cup final last month. An abnormality in the sample resulted in the 27-year-old defender, who cost Celtic a club record £4.5 million from Bolton in July 1996, giving a blood test from which the latest development has arisen.

Stubbs was notified of the problem during his close season break and while his team-mates will return to pre-season training this week, he will be anxiously awaiting the results of the operation.

Stubbs has two years of his Parkhead contract still to run, although he was expected to move back to England this summer.