Serena and Venus Williams bowed out of the doubles tournament at the Australian Open on Wednesday.
The sisters have yet to say why they withdrew.
Venus and Serena Williams have withdrawn from the doubles tournament. No official reason given yet. #AusOpen
— SI Tennis (@SI_Tennis) January 21, 2015MORE: Amazing photos from Australia | Sportal.com's live coverage | Women's top seeds
Serena is the top seed for the singles tournament. She defeated Alison Van Uytvanck 6-0, 6-4 in the first round Tuesday. She has won 18 Grand Slam titles.
Venus, who has won seven Grand Slam titles, is seeded 18th this year and defeated Maria-Teresa Torro-Flor 6-2, 6-2 to move on to the second round in singles.