FEDERER SICK

A virus forced Roger Federer to withdraw from his only Australian Open tune-up as the world No. 1 pulled out of Kooyong starting on Wednesday.

Federer, who arrived in Melbourne on Friday from his training base in Dubai, said doctors advised him to withdraw from the elite warm-up after contracting the severe infection contracted last weekend.

"After arriving in Australia last Friday, I came down with a terrible stomach virus on Saturday and it continued to get worse over the weekend," said Federer.

"After trying to practice on Saturday afternoon, I went to see the doctors and they immediately performed a series of tests. The doctors have advised me that I should take a couple of days off and recuperate so that I am able to be 100 percent for the start of the Australian Open.

"As a precaution, I will need to withdraw from Kooyong. I hope to resume practice by the middle of the week".

Federer was joined as an absentee at the eight-man round-robin tournament which starts on Wednesday by Tommy Haas. Haas had recent shoulder surgery for an on-going problem, but has not recovered in time to take his place in the field. He still hopes to be ready for the Australian Open.

Haas was replaced by Russian world number four Davydenko.

The field will now comprise: Davydenko, Andy Roddick, Fernando Gonzalez, Andy Murray, David Nalbandian, Ivan Ljubicic and Marat Safin.