The Australian Open announced that 2009 champion Rafael Nadal has withdrawn from this year's tournament with a stomach virus.

"I am sorry and very sad to announce that I will not play in the Australian Open," Nadal said in a statement. "My knee is coming along okay, but a stomach virus has left me unable to get ready in time to tackle the rigours of a Grand Slam.

"Because of the virus, I have been unable to get any match practice and simply would not be doing myself or my friends in Australia justice if I went down there so unprepared. You need your body to be at its best for the Australian Open.

"It was a difficult decision and I am extremely disappointed to be missing such a great event. I love coming to Melbourne and playing on Rod Laver Arena before the Australian crowds. It brings out the best in me. It hurts to have to wait another 12 months before I get another chance. In the meantime, the focus is now on desperately trying to get back on the tour."

Nadal previously withdrew from this week's exhibition tournament in Abu Dhabi with a stomach virus, and has also pulled out of Doha, where he was scheduled to compete next week.

Doctors have advised that Nadal take a week-long period of rest without training, beginning today. He will then be examined and have an x-ray in four to five days.

“Rafa suffered last week a viral process that provoked a gastroenteritis with high fever for four to five days,” said Angel Ruiz-Cotorro, who heads Nadal’s medical team and is the director of the Mapfre Center for Tennis Medicine. “Starting next week he won’t be in sufficient physical conditions to continue with his rehabilitation process.”

Rafa’s uncle and coach, Toni Nadal, added that there wouldn't be enough time for Rafael to properly prepare for the Australian Open.

“It is simply not conceivable that his first event is a best of five sets event, he wouldn’t be ready for that,” Toni Nadal said. "It is true we have been quite unlucky with this but there is nothing we can do. After all this time it is better to do things well and the most professional thing to do is to start when we are ready.”

At the Abu Dhabi exhibition, world No. 1 Novak Djokovic told reporters he was surprised at the news, as he and Nadal had been lining up practice sessions.

“Obviously for his situation right now that is quite specific,” said Djokovic. “You can’t compare it to any other player because he’s been off the tour for six months, so I’m sure he lacks matches and confidence and sharpness. I really don’t know what’s happening because no one has seen him six months. I really wish him a fast recovery because he is someone that brings a lot to tennis with his success, his athleticism, his competitiveness, and also he’s a recognized athlete worldwide. It’s not good news definitely.”

Nadal's countryman Nicolas Almagro was also surprised.

“We were talking with him and I talked in the players’ lounge with David [Ferrer] and he told me that Rafa isn’t 100 percent right now,” said Almagro. “He wants to wait a little bit and he doesn’t want to start in Melbourne because it’s five sets and his knees are not ready for that. We are waiting for him and we need to wait until South America. It’s one month and maybe he will be ready.”

In an interview with the London Times last week, Rafael Nadal said that his knee “is still not perfect. The doctors say that the images are very good, so that is a big calm for me, but I still feel something. I need to be careful. I need to be focused on how the knee is getting better or worse every day, and don’t make a mistake that can be negative for my future.

“What will not be important for me is the first point in Abu Dhabi [where he was scheduled to play]. It will be when I feel that my knee is ready. It is not the right time yet to feel these kinds of things. I will have these feelings hopefully at the end of February and the beginning of March—that is when I’m going to be 100 percent fit and when I really start the season and feel ‘Let’s start to win now’.”

Nadal has not played on tour since losing in the second round of Wimbledon to Lukas Rosol. He is targeting the clay-court tournament in Acapulco, in late February, as a return date.