U.S.--Russia Fed Cup semifinal surface selected

The Fed Cup semifinal between the U.S. and Russia will be played in Russia on a clay court. Russia has two clay experts, Svetlana Kuznetsova and Nadia Petrova, though Petrova is not currently on Russia's Fed Cup team. Will she be added? The U.S. has two clay experts in Serena and Venus Williams, one of whom could be added to the team (it's hard to imagine their both being available).