According to the Washington Post, Nationals GM Jim Bowden is upset with his first base situation and will look to add a replacement for 2009. The Nationals primary first basemen, Dmitri Young and Nick Johnson, have both struggled this season having failed to play more than sixty games. While there are not many good free agent first baseman available, they could give a player like Richie Sexson a chance, while finding a legitimate replacement through trade. A good, realistic option would be Kevin Millar, who might not be resigned by the Orioles.
The Nationals want to make a big splash this season, and while I doubt it will be Mark Teixeira, I would not be surprised to see them go after Adam Dunn.