World number one Lindsay Davenport [ Images ] has pulled out of the United States team for this week's Fed Cup semi-final against Russia [ Images ] with a back injury.

"I'm very disappointed that Lindsay would not be able to support our team here in Moscow [ Images ]," U.S. captain Zina Garrison told a news conference on Wednesday.

Garrison said that Davenport, who was treated for a back injury in the third set of her defeat by fellow American Venus Williams [ Images ] in the Wimbledon [ Images ] singles final, could not recover in time to face the defending champions.

Jill Craybas, who pulled off a shock at Wimbledon when she upset Serena Williams [ Images ] in the third round before losing to Venus, has been called in as a replacement.

Davenport's withdrawl is a huge blow for the Americans, who were already missing the younger Williams sister.

The former world number one pulled out of the tie at the Olympic [ Images ] arena following her tearful defeat at the All England [ Images ] Club last month.

She has been plagued by various injuries this season.

In the absence of Davenport and Serena, newly-crowned Wimbledon champion Venus along with doubles specialist Corina Morariu and Mashona Washington will carry the U.S. hopes in Moscow.

The Russians are also missing U.S. Open champion Svetlana Kuznetsova [ Images ] and French Open [ Images ] semi-finalist Nadia Petrova [ Images ], who pulled out with shoulder and leg injuries respectively.

Last year's French Open champion Anastasia Myskina [ Images ] and beaten finalist Elena Dementieva [ Images ] will lead the home team.

The winners will face France [ Images ] or Spain in the Fed Cup final on September 17-18.