Pitching, pitching, pitching, and more pitching, maybe some OF help too. The Nationals basically have some of the worst pitching you'll see (more talent in-game than IRL, but still) and any young pitching you could give up probably would get it done. For the realism factor, keep in mind that the Nats just signed Dunn to a 2yr/$20mil this offseason so they may be a little reluctant to give him up so soon. What team are you, firsttimer?