Seeing as Sharapova probs wont play (and shes not that good on clay neway), i actually think USA will win. I think a hard court would be better
On clay? Against Russia? Not a chance with or without Sharapova. The US with their best line up have a decent shot to beat Russia on any other surface (I'd say a 50/50 prospect) but on clay in Moscow, I really can not see how America have any chance at all.