Juan Martin del Potro withdrew from the Australian Open, citing concerns over the wrist injury that sidelined him for most of last year.
The Argentine, winner of the US Open in 2009, announced his withdrawal in a media conference on Sunday.
Del Potro made his return to competitive action at the Sydney International, reaching the quarter-finals in his first tournament since February.
However, the 26-year-old – who was due to face Pole Jerzy Janowicz in the first round – is unwilling to take risks with his wrist injury.
"I have to be smart," Del Potro said.
"I'm looking forward to my future and my career."
Del Potro, emotional during his wins in Sydney, used mostly slice backhands in his last-eight loss to Kazakh Mikhail Kukushkin.
For the most part, he was unable to hit powerfully off that side – and was punished in a straight-sets loss.
His absence is another blow to the first grand slam of the year, which will already be without Jo-Wilfried Tsonga, Marin Cilic and Janko Tipsarevic.
Japan's Hiroki Moriya, the lucky loser, will face Janowicz.