I don't know why everyone is so set on moving Harper out of center.
He eventually will become a corner outfielder once he fills out more. At this point if LaRoche walks (I think he has by now) then Morse moves to 1B and either the Nats could do a couple of things.
1. Go in house. Either playing Moore everyday in LF or using a platoon of Moore and one of Bernadina or Brown is possible.
2. Leave Morse in LF and use Moore at 1B.
3. Go outside the organization to try and pick up a LF or CF.
If someone was to be picked up in FA, I'd rather it be someone like Pagan or Victorino on a short contract. I think Pagan returns to San Fran and someone will probably overpay on years for Victorino. I'd take B.J. Upton over Bourn, because I value his bat over Bourn's and honestly they both play elite defense in CF.
I still think it makes most sense to look for pitching, but without LaRoche, Harper becomes exposed as the only left handed power hitter. That is unless Espinosa has a much better year, which could happen.