New U.S. captain Mary Joe Fernandez invited both Williams siblings to participate, but they declined, citing scheduling issues, the U.S. Tennis Association said.
"This year, with the new schedule, the new commitments, I don't think it's the best time for me,'' Serena Williams said when asked about the Fed Cup at the Australian Open, where she will play Elena Dementieva on Thursday for a berth in the final.
Without her or older sister Venus - who have won a total of 16 Grand Slam singles titles - Fernandez selected Fed Cup rookie Bethanie Mattek, Jill Craybas, Melanie Oudin and Liezel Huber for the best-of-five series against Argentina on Feb. 7-8 on outdoor hard courts in Surprise, Ariz.
The United States, which last won the Fed Cup in 2000, will take on Argentina's Gisela Dulko, Betina Jozami, Soledad Esperon and Aranza Salut.
Dementieva was the only one of three Russians who reached the Australian Open semifinals picked to play for the defending champions. She will be joined by Svetlana Kuznetsova, Anna Chakvetadze and Alisa Kleybanova for the series against China on indoor hard courts in Moscow.
Dinara Safina and Vera Zvonareva are the other Russians still playing at the Australian Open; three-time major champion Maria Sharapova is injured.
Kuznetsova and Zvonareva teamed with Ekaterina Makarova and Elena Vesnina to sweep Spain 4-0 in last year's final.
China will counter with 2008 Wimbledon semifinalist Zheng Jie, Yan Zi, Zhang Shuai and Sun Tian-Tian.
Also in the World Group, France hosts Italy on outdoor hard courts in Orleans, and the Czech Republic hosts Spain on indoor carpet in Brno.
French veteran Amelie Mauresmo will lead her team along with 16th-ranked Alize Cornet, Nathalie Dechy and Severine Bremond against Italy's Francesca Schiavone, Flavia Pennetta, Sara Errani and Roberta Vinci.
Marion Bartoli, who upset top-ranked Jelena Jankovic at the Australian Open, was left off France's team because the 17th-ranked player insists on having her father, who coaches her, present at Fed Cup training sessions. The French team requires its players to practice under Fed Cup trainer Alexia Dechaume-Balleret.
"I think things could change, and I hope they do so favorably,'' France captain Nicolas Escude said.
Spain will be represented by Australian Open quarterfinalist Carla Suarez Navarro, Nuria Llagostera Vives, Maria-Jose Martinez Sanchez and Lourdes Dominguez-Lino in the Czech Republic against Iveta Benesova, Petra Kvitova, Lucie Safarova and Kveta Peschke.
In World Group II, Jankovic and Ana Ivanovic will play for Serbia on hard indoor courts against Japan in Belgrade.
Also in second-tier competition, it's Slovakia against Belgium, Switzerland against Germany and Ukraine against Israel.
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AP Tennis Writer Howard Fendrich contributed to this report.
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