WIMBLEDON, England (AP) - The Williams sisters could be set for another Wimbledon final after they were placed in separate halves of the bracket in Friday's draw.
The men's draw was rocked when defending champion Rafael Nadal pulled out because of tendinitis in his knees, leaving Roger Federer the big favorite to win a sixth Wimbledon championship and 15th Grand Slam title.
Defending women's champion Venus Williams may have to overcome top-ranked Dinara Safina in the semifinals, while Serena could play fourth-ranked Elena Dementieva in the last four.
The Williams sisters have played each other in three previous Wimbledon finals, with Venus winning last year and Serena taking the title in 2002 and 2003. Venus has won five Wimbledon titles since 2000, including the last two.
Safina, still looking for her first Grand Slam title after losing the French Open final for the second straight year, was drawn against Lourdes Dominguez Lino of Spain in the first round. Venus Williams will take on Stefanie Voegele of Switzerland and Serena plays Neuza Silva of Portugal.
Federer could be aided by a seemingly easy path to the final of the grass-court major.
The Swiss star could face Novak Djokovic in the semifinals, but has few dangerous matchups before then. Federer opens against Yen-Hsun Lu of Taiwan, but could face French Open finalist Robin Soderling in the fourth round and either seventh-seeded Fernando Verdasco of Spain or No. 9 Jo-Wilfried Tsonga of France in the quarterfinals.
The biggest beneficiary of Nadal's withdrawal might be Andy Murray, who no longer has to worry about playing the Spaniard in the semifinals. Murray is looking to become the first Briton since Fred Perry to win the tournament and is coming off a Queen's Club victory last week for his first grass-court title. Nadal's absence is sure to increase the already high expectations at home for a British title.
Nadal's spot in the draw was filled by fifth-seeded Juan Martin Del Potro, who will now play Arnaud Clement of France in the first round. James Blake moves into Del Potro's slot, and the 17th-seeded American's place is taken by Nicolas Kiefer. Thiago Alves enters the draw as a lucky loser, in Kiefer's original spot.
Former women's champion Maria Sharapova, trying to return to form after a long injury layoff, opens against Viktoriya Kutuzova of Ukraine and could face Serena Williams if she makes the quarterfinals.
Safina could meet Svetlana Kuznetsova in the quarterfinals after losing to her fellow Russian in the French Open final.