Fangraphs has released a new tool called WAR Grids. Here you can compare different groups of players and get a visual representation of their WAR (Wins Above Replacement) over the course of their career. I decided to create one looking at the Washington Nationals All-Time roster.
As you can see, Ryan Zimmerman is by far the move valuable player in the Nationals short history. Rather surprising however is that Nick Johnson is number two, after he put up to seasons with a WAR of 5. You have to remember that WAR takes into account defense, which is why Johnson ranks so high, and well, Dunn ranks surprisingly low.
When evaluating Dunn on this chart, you also have to remember that he only spent two years with the team. So while he earned the same total amount of WAR as Cristian Guzman, he earned more per year.