Frenchman Jean Van de Velde's hopes of a return to Carnoustie to play this year's British Open have been hit by a mystery virus.

Van de Velde, whose career was nearly ended by a knee injury four years ago, infamously lost the 1999 major in Scotland by triple-bogeying the 72nd hole before Scotland's Paul Lawrie won a four-hole play-off.

The 41-year-old Frenchman does not yet have a start in next month's major and a debilitating illness picked up in April may have put paid to his chances of qualification by a number of routes.

"I started to feel sick after the Portuguese Open," Van de Velde told a news conference yesterday, the day before he tries to go one better in the French Open than his runner-up spot in 2005.

"I felt tired, had pains in my muscles and I was physically sick but there was a big question mark over what was wrong with me.

"It hasn't gone away. After I hit about 30 balls in practice I have to stop because of tiredness. I have some good days and some bad days."

Victory this week would give Van de Velde a chance of a Carnoustie exemption via a British Open order of merit that ends on Sunday.

If he fails, or if a French win is still not good enough to overtake prime front-runners Richard Green of Australia and Briton Bradley Dredge, Van de Velde will have to go to 36-hole international qualifying at Sunningdale on Monday.

Because of his condition Van de Velde was not optimistic about this week or next Monday.

He said: "I am not in the best condition for the French Open, which is disappointing. I have no expectations.

"I plan to be at Open qualifying at Sunningdale on Monday but I feel it should not be held after a big event like this one."

If Van de Velde does not make it at Sunningdale he has two more chances by finishing first or second in next week's European Open or the following week's Scottish Open.

The Irish challenge at the French Open consists of Paul McGinley, Damien McGrane, Graeme McDowell, Peter Lawrie and Gary Murphy.

Philip Walton, who has been given a sponsor's invite to play in next week's European Open is also in the French line-up.