An on-point Barthel is a threat in the third round. After that, she's basically a shoo-in for the semis. Li or Stosur would be a threat in the quarters, but....let's be honest....will either be able to string enough victories together to even get there? Doubtful.
Of the top 3, Maria is probably the best matchup for Aga (just because the other two are so historically disastrous.) A win in the semis against Maria/Venus/Bartoli/Kerber is doable. Don't see her getting past either Serena/Vika in the finals. Would love for her to prove me wrong though. Or better yet, if someone else from that half of the draw is in the finals.