MELBOURNE, Australia -- As the Australian Open begins, the main question centers on the health of top players. Serena Williams cut last season short after her US Open defeat, then pulled out of the Hopman Cup earlier this month, citing knee issues. No. 2 Simona Halep (sore Achilles), Garbine Muguruza (plantar fasciitis) and No. 4 Maria Sharapova (sore left forearm) all withdrew from the Brisbane tuneup, while No. 6 Petra Kvitova missed two tournaments with a stomach virus.
How will they fare in Melbourne? Here's a look at the women's draw:
Best first-round match
Belinda Bencic versus Alison Riske: Who will eventually replace Serena at No. 1? One of the best young players in the game, the 18-year-old Bencic, is considered a top candidate. She lost to Riske in the finals at Tianjin, but that was in the fall of 2014. She's older and better now.
Luck of the draw
Carla Suarez Navarro: She has made it past the third round here only once, and that was seven years ago. But she won't face a non-qualifier until the third round or anyone ranked within the top 20 until the fourth round, where she could play Kvitova, whom she has beaten their past four meetings.
Upset watch
Sharapova: Counting the Fed Cup, this will be only fourth tournament since Wimbledon last summer for the former world No. 1 (she withdrew before the start of the US Open with a leg injury), and she now is dealing with her left forearm issue.
Contender best positioned for the final (top half)
Serena Williams: She is naturally the top seed, was 26-1 in Slams last year and has won the Aussie six times. Her possible quarterfinal opponent is Sharapova, whom she's defeated 17 times in a row, including in the finals here last year.
Contender best positioned for the final (bottom half)
Victoria Azarenka: The two-time Australian Open champion is healthy again (unlike many of her rivals) and back on the upswing. Depending on Serena's health, she could be the one to watch.
Cinderella candidate
Muguruza: She had a strong first half last year, then a weak summer, then did better in the fall. She won't face anyone ranked within the top 32 until the fourth round. She also has faced and beaten Serena in a major. But plantar fasciitis can be a nagging injury, so she should definitely not wear glass slippers.
American with the friendliest path
Venus Williams: She won't play anyone ranked within the top 30 until the fourth round. Better yet, she wouldn't face her sister, Serena, until the final.
Fish out of water
Roberta Vinci: The Italian upset Serena at the US Open, but don't expect a repeat. One, she would have to reach the Aussie semifinals to play Williams. Two, she has never made it past the third round here.
Most likely to hit the reset button
Sloane Stephens: The American rose to fame after beating Serena in the quarters here in 2013 only to see her career crest and then slide. But she finally won her first WTA title last summer and added another in Auckland this month. She could be ready for a comeback.
Most in need of a good run
Eugenie Bouchard: The Canadian was ranked among the most marketable athletes in sports last year and reached the Aussie quarters in 2015 -- then her career went in the tank. She won only five matches from February through August, including first-round losses at the French and Wimbledon, before suffering a concussion that knocked her out of the US Open. She dropped from No. 7 to No. 47.
Hard luck of the draw
Sharapova: She reached the Aussie Open final last year, but it won't be easy this time around. Not only is she aching, she would have to face dreaded nemesis Serena earlier than last year, in the quarters.
First-round match we don't want to miss
Is there any question? Of course it's Serena! This will be the first time we get to see the world No. 1 player in a real match since the US Open and whether that aching left knee limits her any further.