BARCELONA, Spain (AP) — Just when Rafael Nadal's knee had recovered, a stomach virus has forced the Spaniard to delay his return to tennis by another couple of months.

Nadal announced Friday that he will miss next month's Australian Open and probably won't play again until the end of February, saying he needed time to recover from a stomach virus that already prevented him from making his return at Abu Dhabi this week.

The latest setback comes after being sidelined since June with a knee injury, which forced him out of this year's Olympics and U.S. Open. He had planned to make his return to the ATP tour at the Qatar Open in Doha next month before the Jan. 14-27 Australian Open, but pulled out of both events.

While he is expected to recover from the virus in time for the Grand Slam tournament, Nadal and his team said he wouldn't have the proper preparation to play in a five-set event straight away.

Nadal stressed that his decision had nothing to do with the tendinitis in his left knee, which made him take a hiatus since last summer following a stunning second-round loss to then 100th-ranked Lukas Rosol at Wimbledon in June.

"My knee is much better and the rehabilitation process has gone well as predicted by the doctors," Nadal said in a statement from his hometown of Manacor on the island of Mallorca. "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."

The former No. 1 said he hopes to make his long-awaited return at Acapulco starting on Feb. 27. However, he did not rule out playing at an earlier tournament if his recovery went well.

"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," said Nadal. "I always said that my return to competition will be when I am in the right conditions to play and after all this time away from the courts I'd rather not accelerate the comeback and prefer to do things well."

Nadal's doctor, Angel Ruiz-Cotorro, said in the same statement that Nadal needed at least a week to recover from the virus, ruling him out for the Qatar Open set to start on Jan. 2.

Nadal's coach and uncle, Toni Nadal, said it wasn't an option to go straight into a tournament with a five-set format after been sidelined for so long.

"We consider not appropriate to play the Australian Open since we will not have enough preparation for a greater competition which is a Grand Slam tournament," said Toni Nadal in the statement. "It is simply not conceivable that his first event is a best of five sets event, he wouldn't be ready for that."

Nadal's knee injury prevented the 11-time Grand Slam winner from defending his Olympic singles gold at last summer's London Games, where he was supposed to be Spain's flag bearer in the opening ceremony. He also had to pull out of the U.S. Open and Spain's Davis Cup final against the Czech Republic, which his teammates lost without him.

Nadal, who is currently ranked fourth, won the Australian Open in 2009. Last year, he lost to top-ranked Novak Djokovic in an epic final that lasted five hours and 53 minutes, the longest ever match at the event and the longest men's Grand Slam final on record.

Australian Open tournament director Craig Tiley said he understood Nadal's decision.

"We just hope he gets better quickly and we see him back on the tour as soon as possible," Tiley said. "Tennis fans across the world have been missing him."