Ai is probably the favorite with Francesca close behind. Both are having excellent years. Katarina is steady and a matchup against Francesca would be interesting although I'm counting on Fran to pull through there.
After a terrific run at W, Silvia has struggled to find her form on the hard courts after having some minor surgery performed. I hope she can right herself here quickly and get to a third round match with Ai but she has some tricky matches early.
I'll lump Nicole in the group of dark horses with Tina.