NEW YORK (Reuters) - The absence of the Williams sisters, two of the world's top players, has left the U.S. team facing a daunting task to beat Russia for the first time in over 10 years in this weekend's Fed Cup semi-final.
That means 18-year-old Melanie Oudin, ranked number 31 in the world, will be the top singles player on an American squad that has not beaten Russia since 1999.
The Americans had left a spot vacant for either of the Williams sisters, hoping one of them would be healthy enough to compete in Birmingham, Alabama.
But Venus, the world number four, said a knee injury would keep her out of the semi-final along with her top-ranked sister.
The U.S. team also includes Bethanie Mattek-Sands and the world's top ranked doubles player Liezel Huber with official lineups for the weekend to be announced at the official draw ceremony on Thursday.
World number six Elena Dementieva will lead a Russian team that also includes world number 30 Anastasia Pavlyuchenkova, 62nd-ranked Ekaterina Makarova and Alla Kudryavtseva (77).
The Americans hold a 4-3 edge of Russia in Fed Cup history but Russia has won the last three meetings.
Fed Cup holders Italy play the Czech Republic in the other semi-final in Rome.
(Writing by Frank Pingue in Toronto)