Helickson is pitching really, really well at the moment. I can understand Davey doing a semi-playoff strategy right now, after the horrible April. Why mess with things? But, since Helickson is pitching better than he has in years, giving him a chance to go deeper into games is a wise strategy. If you do it and he melts down, then fine, accept that the fact that he's a glorified long reliever who just happens to start games. The Nats will need a real long reliever in the bullpen who should be designated to come in after Helickson each game and pitch 2-3 innings. It ties up a spot in the pen, but right now, Helickson is way better than a #5 guy.
The Nats rotation right now is best pitcher in baseball as a #1+, another #1 in Strasburg, and three #3 guys in Gio, Roark and Helickson. Very nice.