Six times Australian Open champion Serbian Novak Djokovic will be 14th, after missing half of 2017 with an elbow injury. In November, Nadal had announced the withdrawal from the ATP World Tour Finals citing a knee injury, which also forced him to subsequently pull out of Paris Masters.
Nadal, 31, heads the entry list for the Australian Open and said he will be ready to front up for the first round.
Although Djokovic said he was delighted with his performance, especially his serve, he acknowledged that he was still not in flawless shape.
Tiley's mood would have improved even further after Nadal returned to the court for an exhibition match at the Kooyong Classic.
Wawrinka has been battling a knee injury and has not played since he was knocked out in the first round of Wimbledon a year ago, and the Swiss was one of the major question marks heading into the January 15-28 Australian Open.
Djokovic had a contrasting 2017, starting at No. 2 but losing in a second-round upset at the Australian Open and not playing again after Wimbledon.
The American, who coached the 19-time Grand Slam victor between 2010 and 2013 after being in Pete Sampras' corner, believes that despite recently turning 36, you can never write-off the Swiss because he is such a special talent.More news: Why I am thankful that a new day is on the horizon
For good reason, a two-week grand slam can be described as a "last man standing" marathon of mental and physical endurance, which makes Roger Federer's haul of 19 all the more incredible.
Federer though is heading into the season's first Grand Slam with a lot of confidence after leading Switzerland to season-opening Hopman Cup earlier this year.
Ahead of the first Slam of 2018, Serena Williams' coach Mouratoglou believes there is simply no longer any doubt as to who is the greatest male tennis player of all time. "Hopefully in three or four days I will be there", he said on Thursday.
"It was an fantastic final, an fantastic moment for me in my life and it's great to be back here", he said, per Sky Sports.
She added: "My coach [Mouratoglou] and team always said "only go to tournaments when you are prepared to go all the way".