Here comes Bryce Harper.
With Ryan Zimmerman going on the disabled list, the already-lightweight Nationals' batting lineup faced the loss of a key player, at least in terms of potential. (Zimmerman's slash line was not exactly helping, at 224/324/345, and my concerns were mounting.) NadyRosa are being pushed beyond legitimate expectations of two players who look satisfactory down at 6 or 7 in the batting order, but not so hot going in at #3.
The Nationals are having a great start, and now face an opponent having almost an equally great start. If Harper was going to be promoted at some point this season, this is as good a time as any, no matter how well he is doing at AAA. If he can keep the momentum going, it will add to the Mystique and Aura of Harper. If not, he's got a taste, and maybe will work harder for the next opportunity.