That is the view of Boris Becker, who is concerned the Spaniard will not be up to full speed come his opening match in Melbourne next week.
Nadal sets out on his quest to win what would only be his second ever Australian Open crown this month.
The 32-year-old has been recovering from surgery that ended his 2018 season early last year.
Nadal is the second seed for the Australian Open but heads into the tournament having played no warm-up tournaments.
And Becker reckons the 17-time Grand Slam champion will be OK in Australia – so long as he can get through a couple of matches.
“If it was any other player other than Rafael Nadal, I’d say they would need a couple of tournaments to get back to their best,” Becker told Eurosport.
“But Rafa has shown time and again that he can come back from an injury and play very strong.
“He isn’t getting any younger, and he plays a physical style of game, and perhaps he needs a couple of matches to get into top shape.”
Nadal reached the semi-finals of Melbourne last year before withdrawing injured.
First up for Nadal this month is a tricky clash against Australia’s wild card James Duckworth.
Nadal has been training Down Under hoping to be first for the first Grand Slam of the year.
And Becker trusts Nadal knows what he’s doing by heading into the Australian Open down on game time.
“I know he’s already been in Australia for two weeks – he was going to play in Brisbane but he pulled out,” he added.
“If he didn’t think he’d have a chance, then he wouldn’t be there.
“As long as he can get on the courts and train then he’ll be fine.”
Watch the Australian Open LIVE and exclusively on Eurosport and Eurosport Player from Monday.