Eric Bruntlett is a good fielder at almost every position on the diamond. That would make him a pretty handy 25th man for some teams.
However, he can't hit at all. Last year, at age 31, he struck out in 24.8% of his plate appearances and walked in just 4.5%. He also had no power whatsoever, hitting just seven doubles and no other extra-base hits in 118 plate appearances.
So, terrible contact hitter + no strike-zone discipline + zero power = totally useless with the bat. Indeed, his .214 wOBA in 2009 would have ranked him #15 in the NL if he was a pitcher. The Nationals aren't a team that can afford to carry guys like this and just never let them hit (see: Cintron, Alex).
That doesn't mean this was a terrible singing. I wouldn't want him on my opening day roster, but if there are injuries and you have to bring him up to function as your utility man, that's not too bad.
But he can't be used as an everyday player under any circumstances, and that's what worries me. If the plan is to use Bruntlett as plan B in the even that Ian Desmond flops or Cristian Guzman misses significant time to injury, that's a recipe for another 100-loss season.
Josh Whitesell gives the Nationals something they don't really have anywhere else above AA: a first baseman. He's also not much with the bat (though he's always been able to take a walk), but you're asking for trouble constantly playing guys out of position as the Nationals have the last two years, including Adam Dunn, Josh Willingham, Paul LoDuca, Ron Belliard and Mike Morse.
Like Bruntlett, Whitesell shouldn't be on the opening day roster, but if the Nationals are forced to reach down to AAA at some point, Whitesell is a guy who can at least contribute by standing next to first base and making the routine plays.