Last Friday, approximately 19 minutes before the trade deadline expired, the Washington Nationals traded first baseman Nick Johnson to the Florida Marlins for minor league RHP Aaron Thompson. At first, it’s easy to see why the Nationals parted ways with Johnson. He is a contact hitter at a premium power position who brings little more than above average defense to the table. Sure it was hard to see the last remaining Montreal Expo get forced out of town but the Nationals need better production offensively at first base. Luckily for them, they have Adam Dunn who’s large frame and explosive power numbers make him a great fit at first. But is he really?
To figure this out, first we’ll need to evaluate his defense in both the outfield and at first base. To do this I’m going to use a stat called UZR or Ultimate Zone Rating in Runs Above Average. Basically, UZR determines how many runs a player will prevent compared to the average fielder for that position. To get UZR you have to compile an assortment of factors to include arm, range, and errors compared to the average player at that position. For a better understanding of UZR, I recommend you visit FanGraphs. Anyway, getting back on track, before the trade, Adam Dunn primarily split his time between left and right field(which made no sense to me seeing how he’s pushing 280 lbs). Dunn has played 62 games in LF and according to FanGraphs, his arm accounted for 3.3 more runs scored than the average left fielder allows. If you think that’s bad, Dunn accounted for 9.5 more runs scored with his range, or lack there of. The only positive aspect of his game in left field was that he has less costly errors than the average left fielder allowing just .3 less than the average player. This accounts for a UZR of -12.4 but what’s scary is that his defense accounts for 24.5 more runs score than the league average over 150 games. Think about that. Given his current offensive production it would take him an additional 35 games to make up for it at the plate. So if Adam Dunn is this bad in left field then why did he predominantly play there? Maybe it’s because Dunn is even worse in right field. Hard to believe it but it’s true. With only 22 games in RF, Dunn has a UZR of -7.4 which accounts to a whopping 35.6 runs scored a game thanks to his lack of glovework.
Before you start thanking the baseball gods that you’ll never have to see Adam lumbering around the outfield again, you may want to check out his defensive production at first base. In just 12 games, Dunn already has a UZR of -3.5 at first base which accounts for 35.6 more runs scored because of his poor play than if you had an average fielder there. By comparison, Nick Johnson only allows 7.3 more runs over 150 games. That means, with Dunn at first base, the Nationals give up 28.3 more runs than when Johnson played. This lack of defensive ability by Dunn is made even more important when you factor in the well documented throwing issues Ryan Zimmerman has been having at third base.
So was it really a good move for the Nationals to ship Nick Johnson to a division rival just to get an added boost to the lineup? Probably not but given the fact it was looking unlikely that Nick Johnson was going to re-sign with the Nationals in the offseason, they may not have a choice.
*Note* I am still relatively new to UZR and am still in the process of truly understanding it. If I have made an error in interpreting the importance of UZR, please let me know so I can learn more about how it works.