Given that Rhee campaigned for Fenty, you would think Gray would can her. But as Michael Fiorillo noted in this comment here:
Gray will be under immense pressure to keep Rhee. The malanthropists will threaten to yank the money they're contributing to the pound-of-flesh wage increases in the new contract, Duncan will expectorate on the issue, etc.
Valerie Strauss at The Answer Sheet says whatever Gray does, he should do it soon. I think the longer Gray waits to make a decision, the more likely it is Rhee stays.
Maybe she can just get a full time job bribing the woman sexually harassed by her fiance Kevin Johnson to stay quiet?