From Ana's site:
Ana has been receiving treatment on her right thumb from an chiropractor/osteopath in Sydney over the past week. She has responded well to treatment and has had several successful practice sessions.
Barring any complications, the 20-year-old expects to be ready to compete in the U.S. Open, which begins in New York on Monday 25 August.
I'll believe it when I see it, but this is encouraging.