The Nats overcompensated for the recent loss of Adam Dunn to the White Sox by signing Jayson Werth to a seven-year deal for $126 million. That’s $18 million a season.

The most optimistic reactions I’ve seen say they only overpayed by $8-10 million, but it’s still a lot of money to give someone who’s only really been playing full-time for three years and is already 31. I mean, this is what I expected Carl Crawford to get, since he has been the face of a franchise for almost a decade. Werth has been the third- or fourth-best hitter on the Phils for three years (Howard, Utley, Rollins’ MVP year, Werth).

In terms of offense, this makes up almost exactly for the loss of Dunn. Dunn had more power, but Werth has more speed. The big difference is on defense. While Dunn is terrible in the field, Werth is above-average as a corner outfielder. He’s also played some center, where he’s passable.

You’d be surprised how much of a difference good defense makes. After I first wrote this, I went back and checked the WAR (Wins Above Replacement) numbers from fangraphs, and was startled to see the difference between Werth and Dunn.

Werth’s WAR last 3 years:

2008: 5.1
2009: 4.9
2010: 5.0

Dunn’s WAR, last 3 years:

2008: 1.1
2009: 1.2
2010: 3.9

Before Dunn switched to 1B, a position he is merely “not terrible” at, he was nearly giving up as many runs in the outfield as he was producing with the bat. His net value was basically the same as Ian Desmond or James Loney’s.

Once he switched to 1B, however, Dunn’s offensive contributions shined–but they still didn’t match Werth’s total package. In terms of overall value, Werth is better than Dunn. We should see a significant improvement in next year’s team.

I’m not sure that he is worth signing for three more years at $4 million more a year than Dunn was. What could make this signing worthwhile is the addition of a decent bat at first.

Over the last three years, Adam LaRoche has been about a 2-win 1B (WAR: 1.7, 2.6, 2.1).

Although 2010 was a down year, Carlos Pena has a better 3-year average, and can also probably be counted on for about 2 wins (WAR: 4.0, 2.8, 1.0).

Derrek Lee might be another good option, given that he has been worth at least 2 wins each of the last three seasons, and might experience a bounce-back (WAR: 3.2, 5.2, 2.0).

Werth plus any of these guys–Pena, LaRoche, or Lee–is a better combination than Dunn and Bernadina. If they follow up on the Werth signing, the core of their lineup could all be guys who can hit 20 home runs—Zimmerman, Werth, Pena/LaRoche/Lee, Willingham.

That’s a respectable core, though it’s certainly not going to support a poor pitching staff.It’s too bad the Nats missed out on Javy Vazquez, because a pitcher like that, who can give you 200 IP with at least a 4.00 ERA (and might even have a star season like he did in Atlanta), addresses the team’s bigger need.

What does our rotation look like for next year? Jordan Zimmerman, Yunny Maya, Jason Marquis, John Lannan, Livan Hernandez. I see a whole lot of question marks and No. 4-5 guys. And since it’s been such a tough market for finding pitching help this winter, most of the guys they might have targeted have already signed elsewhere. Signing Werth is not a terrible move, because they needed to replace Dunn, but it is a lot of money and probably limits their reaching for a No. 2-3 starter.

As a baseball analyst, I’d probably grade this move a C+.

They probably spent more money than they needed to, but they addressed a need for more offense.

As a Nationals fan, I’d probably grade this move a B-.

They gave up a lot of money, but they showed they are trying to put a good product on the field. I hated losing Dunn, because, as a fan, I’d grown attached to that Will Ferrell-y face.

But when a new stadium is half-empty at every game Strasburg didn’t pitch, you know you need another draw—and that’s what Werth can be.

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