Mariano Puerta of Argentina and Radek Stepanek of the Czech Republic were seeded on Sunday as the top two to lead the Japan Open Tennis Tournament this week after Australian Open champion Marat Safin withdrew.
Russia's Safin posted his second grand slam title at Melbourne in January, but has not fully recovered from a left knee injury which forced him to skip the US Open a month ago.
To the disappointment of fans, the Argentine duo of 2002 Wimbledon runner-up David Nalbandian and last year's French Open champion Gaston Gaudio, and Britain's Tim Henman, also joined Marat on the injury list.
The 860,000-dollar event gets under way Monday with top seed Puerta, second seed Stepanek and other top 14 players receiving first-round byes.
Puerta, the runner-up at the French Open and the winner at Casablanca this season, will take on a qualifier in the second round - the winner between American Eric Taino and Tasuku Iwami of Japan.
His top quarter includes 14th seed Ivo Minar of the Czech Republic, 12th seed Cyril Saulnier of France, and fifth seed Mario Ancic of Croatia who will play either Peter Wessels of the Netherlands or American Jan-Michael Gambill.
Also in the top half were Americans Robby Ginepri, third seed; Vincent Spadea, eighth seed; Luxembourg's Gilles Muller, 13th seed; and former Japan Open winner Kenneth Carlsen of Denmark, 10th seed.
In the bottom half with Stepanek were last year's finalist Taylor Dent of the United States, fourth seed; Mikhail Youzhny of Russia, sixth seed; Jarkko Nieminen of Finland, seventh seed; and Asia's number one Paradorn Srichaphan of Thailand, ninth seed.
Fresh from her first victory of the season at the Korea Open Sunday, 16-year-old Nicole Vaidisova of the Czech Republic will lead the women's field as the second seed alongside top seed Vera Zvonareva of Russia.
Other seeds were number three Tatiana Golovin of France; number five and former Japan Open winner Ai Sugiyama; and India's rising star Sania Mirza, seeded eighth, in the top half. Vaidisova was drawn with fourth seed Maria Kirilenko of Russia, sixth seed Gisela Dulko of Argentina and seventh seed Shinobu Asagoe of Japan in the bottom half.