Top players pose before 2012 WTA Championships in Istanbul.
The Grand Slams are over. The biggest prize remaining in women's tennis is one of the eight slots in the WTA Championships.
The tournament takes place Oct. 22-27 in Istanbul.
Qualifying is akin to vying for entrance to the NCAA tournament in basketball. However, there's no selection committee. Each player has to play her way in.
The championships feature a round-robin format that feeds into a four-player single elimination finish—the final four.
Qualifying for the tournament is based on points accumulated this year.
Results from the Pan Pacific Open in Tokyo and the China Open in Beijing will help determine who gets the final three spots.
There's a chance Sharapova might withdraw. She is still nursing a shoulder injury.
If a player withdraws, the player with the next highest points gains entry.
Those who don't qualify can still get into the Tournament of Champions—the WTA's equivalent to the NIT.
Petra Kvitova during match against Venus Williams at Pan Pacific Open in Tokyo.
Sara Errani entered the Pan Pacific Open with a lead over the remaining field.
However, she now finds herself in a battle for the sixth spot with Petra Kvitova.
Kvitova won the Pan Pacific Open and leap-frogged over Errani.
How they finish in Beijing will settle this fight. It's played on a hard court, which usually means a hard time for Errani.
Winner of the event in 2011, Kvitova is playing great tennis right now.
Petra Kvitova and Angelique Kerber pose with trophies from Pan Pacific Open.
If Errani or Kvitova fall early in Beijing, Angelique Kerber could sneak past them for the seventh spot.
Kerber had been in a little slump until she reached the finals at the Pan Pacific Open. Although she lost to Kvitova, she won enough points to control her own destiny in qualifying for the year-end championships.
If she finishes ahead of Errani in the tournament, that should be enough to give Kerber her second consecutive trip to tennis' big dance.
Jelena Jankovic at the Pan Pacific Open.
What a year Jelena Jankovic is having.
The former No. 1 player climbed from a 2012 year-end ranking of No. 22 back into the top 10.
Right now, she's ninth in the race to Istanbul. Reaching the quarterfinals in Tokyo has given Jankovic the inside track on the eighth slot.
However, Sloane Stephens, Caroline Wozniacki and Roberta Vinci are close enough in the points race that a poor showing in Beijing could leave Jankovic out.
Caroline Wozniacki at Pan Pacific Open Tokyo.
Gaining entrance to the year-end championships would make Wozniacki instantly relevant again.
Reaching the semifinals in Tokyo helped. Now Wozniacki has a real shot at making the tournament.
Depending on results in Beijing, she could even leap-frog Jankovic.
Sloane Stephens in first-round action at the Pan Pacific Open in Tokyo.
Stephens' loss in the second round in Tokyo hurt her cause.
However, she still has a chance to sneak into what could be a career-changing tournament for her.
If Sharapova withdraws, an additional spot opens up. Right now, Stephens needs to go deep into the tournament in China and hope that those ahead of her fall early.
Stephens' biggest competition comes from Roberta Vinci, who has qualified in the doubles event with partner Errani.
If Stephens wants to play in the "big girls'" tournament, she can't afford an early exit in Beijing.