In 2005, when the Nationals finished last in the NL East (though pretty interestingly), their position players averaged 29.3 years of age and their pitchers 28.9.
In 2006, when the Nationals finished last in the NL East (and rather uninterestingly, at least in the non-Soriano and -Zimmerman senses), those figures were 28.5 and 28.9, respectively.
[editor's note, by Basil] I should clarify that BaseballReference.com makes no indication those figures were Livan-adjusted. For the sake of this exercise, let's abide the fiction that Livan isn't actually 84 years old.
I wonder what those figures will be for the 2007 season. Any guesses?