With the 40-man issues we're headed for in the next month or so and the extra pitching depth we'll have with Hutch and Drabek coming back, there's no point to bring RR back until you're as sure as you can be he's back to his old self.
The team doesn't need to further complicate their roster crunch, and Ricky sure as hell doesn't need to come back up prematurely to get bombed.