The Nationals are Buyers
This is a foreign situation to Nats fans so let it first be said that being a buyer is difficult. It could very well hurt. A GM of a buying team is trying his best to make it not hurt by trading from positions of strengths to fill a weakness, but selling teams are not going to accept short term pieces back in a deal. In other words the Nationals can't trade Michael Morse to a seller who views themselves being more than a year away since Morse is only signed for one more season after this. Selling teams are going to want long term, controllable pieces. In other words they want prospects or young major leaguers.
Players like Danny Espinosa or Tyler Moore could have great value to a seller even though they are no longer prospects because they are both young and controllable major league players. Trading Moore would hurt worse than trading Espinosa as the Nationals lack a first base prospect for the 2014 season unless Anthony Rendon or Matt Skole hurry up the development ladder faster than projected, but this is part of the trick of trading. If Rizzo values one of those two higher than he does Moore and believes he can fill the gap at first base with at least a league average player until Rendon or Skole arrives then Moore can be traded without it hurting the future of the Nationals. The same goes for Espinosa and how the Nationals value Lombardozzi or Kobernus.
It is also important to not view trades in a vacuum. The Nationals need a centerfielder who can run down baseballs and the Reds or Angels need pitching. The Nationals could trade either Clippard to the Angels for Peter Bourjos or Edwin Jackson to the Reds for Drew Stubbs and Ryan Hanigan. Both moves weaken a position of strength for the Nationals but strengthen areas that are weaknesses. The Nationals could then turn around and trade prospects for a pitcher like Matt Garza or Edison Volquez to fill the pitching void. Likewise if the Nats were to trade Espinosa in some sort of blockbuster deal they could then go get Marco Scutaro to help them finish out the season and then sign Kelly Johnson in the off-season if they do not believe Lombo can play the position full time.
The idea of the trade deadline for buying teams is to increase the odds of winning a World Series. Right now the Nationals have decent odds, but do not stack up well on paper against the Yankees, Rangers, Angels, and look to be even with the Giants and Reds. Any move the Nationals can make that can increase those chances should be made.
Now a lot of people are worried about the Nationals trading away the future. The future of the Nationals franchise is currently locked firmly into two names; Stephen Strasburg and Bryce Harper. Anything happens to those two and suddenly the Nationals bright future turns into a grim reality. Teams don't get a lot of opportunity to go for it, and MLB is making sure with their new CBA rules that windows are going to close faster than ever. Hoping and banking on Alex Meyer to step into the rotation and replace Jordan Zimmermann after the 2015 season is nice, but if Alex Meyer doesn't make it as a starter or the Nationals retain the services of Jordan Zimmermann he is expendable, and even if the Nationals do neither of those things they can always fill the third starter role via free agency.
If the Nationals do continue to win and fill Nationals Park they will be able to afford and attract better talent on the free agent market making it less of an issue when they do decide to give away prospects in order to get major league talent that can help them to increase their chances to win a World Series. That is what this window opening is all about after all. It would be nice to win 8 division titles over the next 10 seasons, but if there isn't a World Series in there somewhere then in many ways it is all a failure.