"My body is already giving me a lot of problems," the 22-year-old Belgian said.
The Belgian injured her right leg in an awkward slide to the net during a third-round match against Switzerland's Patty Schnyder.
The duo meet in the semi-finals of the German Open.
Serena Williams was left all alone trying to crush an unlikely uprising on Wimbledon's hallowed lawns on Tuesday as sister Venus and Kim Clijsters suffered shock defeats in the women's quarter-finals.
The defending champion continued her comeback with a victory over Martina Mueller.
Belgium's Kim Clijsters raced into the third round at Wimbledon on Wednesday courtesy of a 6-3, 6-2 win over Croatian Karolina Sprem. Justine Henin took a hesitant step towards a first Wimbledon title when she came through her second-round contest 6-3 7-5 against Germany's Kristina Barrois.
Rafael Nadal and Kim Clijsters swept into the Australian Open third round on Thursday as Serbia's Jelena Jankovic became the first top-10 player to exit the tournament. After three days of scares but no upsets at Melbourne Park, former world number one Jankovic, the seventh seed, was dumped out 7-6, 6-3 by Chinese upstart Peng Shuai.
Kim Clijsters's final ride at the Australian Open gathered momentum on Thursday when she motored into the third round with a 6-3 6-0 win over Japan's Akiko Morigami.
Belgian pair Justine Henin and Kim Clijsters will meet in the semi-finals of the Sony Ericsson Open after both advanced through their quarter-final ties on Wednesday.
Martina Hingis played spoilsport at the Australian Open on Monday by denying China another entry into the record books.
She survived a ferocious fightback from China's Li Na on Thursday to book her place in the Sydney International final against in-form Serb Jelena Jankovic.
However, Jelena Dokic was upset by qualifier Maria Vento-Kabchi in the Bank of the West Classic.
The world number two she has to give her wrist more time to recover from a recurrent injury.
A complete round-up of the morning session of play at the Australian Open.
Kim Clijsters was courage personified as the defending champion shook off a painful ankle injury and saved four match points to overhaul China's Li Na 4-6, 7-6, 6-4 and reach the quarter-finals of the Australian Open on Sunday.
Belgian Kim Clijsters brought a swift end to Venus Williams's 15-match winning streak with a 6-2, 6-1 win in the Sony Ericsson Open final on Saturday. The 14th seed needed only 58 minutes to defeat the third-seeded American, who played with bandaging on both legs and said afterwards she may have trained too hard during the tournament.
Top seed Svetlana Kuznetsova was bundled out of the Indian Wells WTA tournament on Saturday, piling up unforced errors in a 6-4, 4-6, 6-1 loss to Spaniard Carla Suarez Navarro in the second round. Twice champion and former world number one Kim Clijsters of Belgium had a much easier time on a sunny afternoon in the California desert, cruising into the third round with a 6-2, 6-1 demolition of Czech Barbora Zahlavova Strycova.
Ana Ivanovic will meet Kim Clijsters in the Cincinnati Open semi-finals after progressing along with Russian teenager Anastasia Pavlyuchenkova and Maria Sharapova on Friday.
The Indian ace dropped two places to be ranked 34th in the WTA rankings
American eighth seed Mardy Fish, however, became the first men's top-10 player to depart the tournament when he crashed out in straight sets to Colombia's Alejandro Falla 7-6, 6-3, 7-6.
Kim Clijsters pulverised Spain's Carla Suarez Navarro 6-1, 6-3 to reach the third round of the Australian Open on Thursday, before laughing off a joke about her "looking pregnant."
Kim Clijsters avoided following US Open champion Sam Stosur out of the Brisbane International tournament when she beat Iveta Benesova 6-3, 6-2 on Thursday to advance to the semi-finals.
The Belgian whipped Lindsay Davenport to reach the final of the Acura Classic. She meets Justine Henin-Hardenne.
Kim Clijsters began her farewell appearance in Miami by beating Akiko Morigami 4-6, 6-0, 6-0 in the second round.
Kim Clijsters will not have played a match in almost two months when she returns at the French Open but if anyone can make a big impression after a lengthy absence the Belgian can.
Kim Clijsters lost the first set but roared back to beat Germany's Kristina Barrois 4-6, 6-2, 6-0 in the second round of the Paris Open on Wednesday.
Kim Clijsters, the long-running success story on New York's Grand Slam stage, is as ruthless on court as she is supportive off it.
Kim Clijsters came through a major test of her early season form to reach the Sydney International final with a 4-6, 6-3, 7-6 victory over Alisa Kleybanova on Thursday.
Kim Clijsters beat Romania's Alexandra Dulgheru 6-1, 6-2 in her first competitive match of 2011 to ease into the second round of the Sydney International on Sunday.
Former world number one Ana Ivanovic will warm up for next year's Australian Open at the Brisbane International tournament, organisers said on Thursday.
Belgians Kim Clijsters and Justine Henin pounded their way into the fourth round of the Sony Ericsson Open on Sunday but Martina Hingis fell to a Polish teenager