Former world No. 1 Rafael Nadal announced Friday he will not participate in the 2013 Australian Open due to a stomach virus.

Nadal has been sidelined with a knee injury since his surprise second-round Wimbledon exit to Lukas Rosol.

The Spaniard was forced to pull out of an exhibition tournament in Abu Dhabi this week due to the illness.

"As my team and doctors say, the safest thing to do is to do things well and this virus has delayed my plans of playing these weeks. I will have to wait until the Acapulco tournament to compete again although I could consider to play before at any other ATP event," Nadal said in a statement on his Facebook page.

"My knee is much better and the rehabilitation process has gone well as predicted by the doctors, but this virus didn't allow me to practice this past week and therefore I am sorry to announce that I will not play in Doha and the Australian Open, as we had initially scheduled."

The 11-time Grand Slam winner lost to Novak Djokovic in last year's Australian Open.