Five-time finalist Andy Murray withdrew more than a week ahead of time, deciding to have surgery on a right hip problem that had kept him off the tour since Wimbledon.
But the father-of-four said at his age and in his 19th Australian Open, he liked to play down his chances. We saw last year's version set the stage for resurgent years from Roger Federer and Rafael Nadal, and it wouldn't be at all surprising if the 2018 tournament played out in a similar fashion. The main issue for Nadal is fitness; he hasn't played a competitive match since mid-November and pulled out of a recent warm-up event in Brisbane, citing a knee injury.
We'd like to give you all of the top contenders' thoughts on their Australian Open chances, but it looks like some of them been having too much fun.
Nadal, who is gunning for a 17th major title but only his second Australian Open crown, is making up for lost time from a knee injury at the tail-end of the 2017 season.
".I'm excited. I think Australian tennis is in pretty good hands at the moment".More news: Iran Reproves US Sanctions Which 'Cross All Red Lines,' Vows to Respond
So he has not completely missed the Australian Open, and did not rule out turning up when it starts on Monday, but it will be the first time since 2005 that he is not here as a participant.
And so if the 2017 Australian Open was one for the ages - the revival of the Federer-Nadal rivalry and another Williams sisters final - the 2018 edition is shaping up as a survival of the fittest.
Federer will saddle up for a 19th time in the main draw at Melbourne Park, looking to frustrate "Generation Next" once again and defend the title he won previous year during a stunning comeback from knee surgery.
No man has more Australian Open titles than Djokovic, who has six in all and - until last year's shocking second-round exit - had won five of the six contested from 2011 to 2016.
Another Federer victory would shunt the grand slam record-holder onto equal footing for the most Australian titles with Djokovic and Queenslander Roy Emerson, who both have six.More news: Bernard Tomic slide continues with Australian Open failure
'Last year was more of a "let's see what happens" kind of tournament, maybe similar to what Novak or Stan [Wawrinka] or others are going through this year, ' said the 19-time Grand Slam victor. "I think it's going to be helpful again for me this year because the court plays exactly the same in Perth and here in Melbourne", he said. But perhaps the biggest threat looming in that quarter is Nick Kyrgios, who could be eying bigger things after intermittently showing just how good he is previous year.
On the men's side, it's a couple of old guys-who played nothing like old guys in 2017-who stand as the two favorites: Rafael Nadal and Roger Federer. I don't know what's going to happen.
"I want to keep it even-keeled throughout the whole year rather than being such a rollercoaster ride". "I feel relaxed", he said.
"It hasn't been 100 percent yet healed".
"I still know what I'm capable of, and I believe in my own abilities to win against the best players in the world", he added ahead of his opening round clash against American Donald Young, also Tuesday.More news: Trump uses expletive in immigration remarks
"If he wins the title tonight he goes to 80th in the world which is right up there with some of the best players in the world".