All caveats about unnamed sources apply. Always take this kind of report with a grain of salt--the sources more often than not are player agents or third-party GMs trying to advance their own interests, not share info.
But, then again, these reports aren't always bogus, and Kenny Williams certainly has a track record of bold strokes to win now. So, let's assume for the sake of argument that the report is true, and that Sox have offered anyone in their farm system, plus Daniel Hudson and Dayan Viciedo. Is there a deal here?
First, let's measure the value of what the Nationals would be giving up. Dunn is under contract for the rest of this season at a salary of $12 million. Using wOBA to measure offense and UZR to measure defense, Dunn has been worth 3.0 wins above replacement this year, putting him on pace for 5.1 WAR for the season. For context, 2-3 WAR is typically a starting caliber player, 5 WAR usually is an all-star, and 8 WAR is typically MVP.
This is a pretty solid measure of his value, although one caveat is that one of UZR's shortcomings is that it doesn't measure the value of runs prevented by first baseman catching errant throws, or "scoops." Dunn's height allows him to catch some balls other first basemen wouldn't get too, but he comes off the bag way way way too much and generally doesn't do his fellow infielders many favors. So we should shave maybe half a win off for that.
Also, you lose another half win for the positional adjustment from first base to DH (more players can "play" DH than first base).
Regardless, for a team in the hunt, adding even a 4.0 WAR guy like this with 70-ish games to go is a big addition. And since the White Sox are in a race that will go down to the wire and have used Mark Kotsay at DH more than any other player this year, and Juan Pierre is a giant sucking sound (ask your grandparents) in left, Dunn could easily be the guy who makes their year.
Now, on the Nationals' side, they are obviously going nowhere this year. They are 40-53, putting them on pace for 70 wins. And of course the trendline is not good, so they're probably on track to narrowly beat the pre-season over-under of 67 wins. If they trade Dunn, they probably replace him with a combination of Mike Morse, Willie Harris (and move Willingham to first), and Justin Maxwell. Those guys should provide replacement level value--not much more, but probably not less.
So trading Dunn might push them down to 67 or 66 wins. And any way you measure it--financially, emotionally, whatever--the difference between 69 wins and 67 wins is basically nil. Even y'all who sit and watch every game in the front row, I'm sorry, you don't really care about 2 more wins.
Then there's the potential opportunity cost of the draft picks that the Nationals would get if they kept him and offered him arbitration, assuming Dunn would decline and become a free agent. It's not totally clear to me that the Nationals would offer him arbitration or that he wouldn't accept it if offered. Still, you have to factor in that value.
Since Dunn's contract is up at the end of the season, that's really all that's at stake here. If the Nationals traded him to Chicago, Dunn would probably be back on the market this winter. That's because the Sox are pretty unlikely to give him a long-term contract given their $103 million payroll, Paul Konerko becoming a free agent, and long-term commitments to Jake Peavy, Alex Rios, and Mark Buehrle.
If the Nationals think Dunn is the key to their playoff hopes in 2011 or 2012 (it's gonna take way more than that--more on that another time), then they can pony up another $20 million or so and get him back.
Now, let's take a quick look at the White Sox prospects:
- Daniel Hudson: at age 23, he put up a 108:31 strikeout to walk ratio in 93.1 innings at AAA Charlotte. He was the #66 prospect on the Baseball America top 100 at the start of the year, and his stock has only gone up. If Hudson is offered, it's an absolute no-brainer, even if the Nationals have to eat salary and throw in Craig Stammen.
- Jared Mitchell: Mitchell, a super-fast centerfielder and lead-off man who showed advanced OBP skills as a 20-year-old in A-ball in 2009, was actually the top prospect in the White Sox system going into the year. Then, he tore a tendon in his ankle. Given the importance of the speed tool for Mitchell, you'd rather wait till he's fully rehabbed. Then again, you'll never get him for a 2-month rental of Adam Dunn after he's fully rehabbed. I'd rather have Hudson, but this is still an easy "yes," unless there's some bad medical news we don't know about.
- Tyler Flowers: Flowers is a major league-ready bat with good OBP skills and decent pop for a catcher. He came to the Sox in the Javier Vazquez trade. The report is that the White Sox offered "anyone in the minors," but it would be hard to trade the heir apparent to free agent A.J. Pierzynski. But, if they do, again, this is a trade the Nationals should do in a heartbeat. Derek Norris is taking a step back, who knows about Jesus Flores, and you can never have too many catchers.
- Dayan Viciedo: You've probably heard of him since he's playing third base now. The Nationals could bring him in and make him a first baseman, which is probably a better long-term fit anyway. I'm not much of a fan. He's a fat hacker with a four-year, $10 million major league deal. I wouldn't be super excited about this, though it's still a good value.
- Jordan Danks: Danks is also close to breaking through at the big league level. He hasn't set the world on fire at AAA, putting up a .243 / .314 / .377 line. But he's a plus defender, and the Sox say he's battled injuries this year and remain high on him. Again, this would be a fair value, but you'd choose others ahead of him.
- Brent Morel: BA's #3 prospect going into the year, he's a very good all-around player and a pretty safe bet as a quality major league regular. But, he's a third baseman. In a vacuum, it's a great value, but not for the Nationals.