Maria Sharapova of Russia at the WTA Shenzhen Open tennis tournament. Photo / AP
Serena Williams' quest to equal Margaret Court's all-time record of 24 Grand Slams will have to wait.
The 36-year-old says she is not physically ready to return to the game four months after giving birth to her daughter and leaves the women's tour still without its pinnacle figurehead.
With no dominant force emerging during Serena's pregnancy and maternity leave in 2017, who, if anyone, will take up the mantle this season?
Nigel Sears, who previously coached Ana Ivanovic and now coaches Russian left-hander Ekaterina Makarova, believes an incredible 26 players could make a name for themselves this year.
Sears, the father-in-law of Andy Murray told The Tennis Podcast how wide open the field is, more so than last year, and is excited for the campa ign ahead.
"If you thought last year was an open year, then you wait for this one," he said. "I think we have to consider 26 players that could make an impression this year. I look at 13 of those dead ringers to have a great year. Another 13 others will very possibly have a great year.
No one player will prove superior over the rest, we have narrowed the net to include ten names divided into five categories who we predict could have a stellar year.
Venus Williams doesn't dwell on her age — now 37 and a half years old for those who do care — but statistically she would become the oldest player male or female to win a major in the Open era if she adds to her seven Grand Slam titles this season.
Twenty years after her first appearance in Melbourne where she reached the quarter-finals, Williams looks in top physical condition and very relaxed as she dances her way through practice sessions.
For Petra Kvitova life back on tour gives her the chance to help erase the mental scars of the awful knife-attack which nearly robbed her of her career.
Now over a year since an intruder posing as a utility worker attacked Kvitova in her old apartment in Porstejov, the 27-year-old has a newfound appreciation for life.
"If I wasn't playing tennis, I don't think I could be as positive as I am now — but it's not pleasant to see those flashbacks. It is a time that I try to forget but I know I will never really forget what happened. This experience has shown me how hard I can work if I need to and just how much of a fighter I am on and off the court."
Garbine Muguruza can be classed as an established force with two grand slams to her CV. The Spaniard is the all-round package. A powerful presence on the court she exudes passion and personality off it too.
Her Wimbledon success put to bed those who wondered whether her French Open triumph in 2016 would be a flash in the pan. The only issue is whether the 24-year-old has the hunger and desire at the events outside of the majors and Masters 1000s.
Love her or loathe her, Maria Sharapova, who is returning to the scene of the slam that led to her failed drugs test two years ago, has the experience, resolve and status to make her presence felt on the circuit again.
The 30-year-old would love nothing more than to respond to her critics and haters by winning a sixth Grand Slam and a second in Melbourne.
Her cause in Australia is assisted by Serena's absence, although the next installment in their head-to-head clash is one the world can't wait to see resumed. Expect fireworks.
Angelique Kerber has an altogether different reason to wag an imaginary 'told you so' finger at her critics than Sharapova.
Kerber had a season to forget in 2017. Starting as world No 1 she finished No 22, without a title and didn't bother picking up a racket for five weeks when the tour was finished.
The off-season has allowed her to get her headspace right and make changes being the scenes with coach Wim Fissette replacing Torben Beltz and a new fitness coach coming on board.
The new voices around the 29-year-old German should inject some fresh life and confidence into a player who wants to archive 2017 and never revisit.
Simona Halep, meanwhile, shouldn't need to prove a point given she tops the world rankings. But the validity of her standing without a major to her name weighs heavily on her shoulders.
A couple of weeks ahead of the Aussie Open and one bookmakers had Halep as low as sixth favourite to win the title.
Those odds have since come in, but until she gets that maiden slam under her belt, the doubters will not go away.
Halep is a player who thrives on self-belief. If she can rid herself of her demons and stay focused in the present, she is more than capable of breaking her duck.
Jelena Ostapenko's stunning French Open success last year was a breath of fresh air for the women's game.
The Latvian has recruited experienced coach David Taylor in the off-season while the 20-year-old's mum will remain her day-to-day coach.
Her fearless approach will draw in the crowds, but her unpredictability could result in a fair few earlier than expected exits.
Belinda Bencic, meanwhile, could take over the Swiss Miss title vacanted by Martina Hingis.
Hingis signed off for a third and final time in her career at the end of last year with Bencic waiting in the wings to become the new darling of Swiss tennis.
Alongside the Swiss master Roger Federer, the pair won the Hopman Cup in Perth as the 20-year-old continued the new season in the same vein she ended the last.
Bencic finished 2017 with 15 straight wins and three straight titles at Futures events. The WTA breakthrough player of 2015, Bencic could finally fulfill her undoubted talent on the big stage.
Julia Goerges heads into the season as the form player after continuing her unbeaten run from last year.
The 29-year-old won her 14th straight match for her third successive title with victory over world No 2 Caroline Wozniacki in Auckland last week.
Goerges is at a career-high 12 in the world, yet has not progressed past the fourth round of any slam. She puts her renewed vigour and success down to her coaching staff.
"I have become much more mature, that's thanks to my team who have really changed my brain."
New Yorker Coco Vandeweghe is another whose on-court behaviour divides opinion.
Her brash exterior and no-nonsense style isn't everyone's cup of tea but she's beginning to build a sustainable style that is reaping rewards on the court.
That in part is largely to do with the connection she has with coach Pat Cash. The blossoming friendship and mutual respect is clear to see and Cash is the perfect match for the unpredictable and fiery 25-year-old.
Aside from the French Open, Vandeweghe was a strong performer at last year's slams, reaching the semi-finals in Melbourne and Flushing Meadows and the Wimbledon quarter-finals.
It would be of no surprise if she was to go one step further this season. The women's game needs another strong personality to sustain interest in Serena's extended absence and Vandeweghe ticks all the boxes.