BiL - I disagree is you mean we "can do better" through free agency. Sad truth is, after Greinke and Sanchez, and Haren if healthy, Jackson is probably the next best pitcher on the market. I don't think we end up with any of the three others on reasonable terms. Then we will be looking at injury recovery guys who are overlooked by others, like McCarthy or Marcum, who aren't lower risk / higher reward relative to Jackson.
Unless the Nats trade a combination or all of Rendon, Meyer, and Goodwin, you are very right. I don't see the Nats having the "bullets" to trade prospects for a guy like Shields or Price. No team that I know of right now is shopping MLB pitchers for MLB talent but someone can always call Jack Zduriencik and inquire about the King!
