The 32-year-old Spaniard is set to take on the victor of the match between France's Jo-Wilfried Tsonga and Thanasi Kokkinakis of Australia on Thursday at the Brisbane International.
"I will probably be 100 per cent in five days".
The Australian Open starts on January 14 and he'll arrive out of rhythm, as was the case a year ago when he couldn't play any matches in the build-up to the tournament before retiring with injury in the quarter-finals.
He lost to South African Kevin Anderson in his only match at the Mubadala exhibition last week, withdrawing from the event after the defeat.
"I tried to play and I still wanted to play but the two doctors from here and the doctors from my confederation in Spain tell me. if I play here, there is a risk (I won't) have the chance to play Melbourne", Nadal said.
It continues a trend for Nadal, who withdrew or retired mid-match during all but one of his hard-court tournaments last season.
"After a long period of time without competing, I felt a little bit the leg, the tightening in Abu Dhabi the first match", he explained.
'I did an MRI and it shows a small straining on my left thigh.
"It's a small thing that can become a much bigger. when you compete, the intensity on the muscle it can get worse", Nadal was quoted as saying by the tournament organisers", Nadal was quoted as saying by the AP. "My hope is to win the Australian Open", said Rafa.
"For me it's a big goal to be ready for there [Australian Open] and I'm going to fight for it", Nadal added.
But Nadal said he would remain in Brisbane until the weekend to prepare for this month's opening grand slam, insisting he could prove his fitness in five days in a bid to claim a second Australian Open title.
"If I play like I played past year, I played so well all the tournaments that I played, and at the end I have a chance, fantastic".