Carlos Pena and Adam Dunn don't seem that different. Both bat left-handed, play first base and filed for free agency. Both are what you might call "three true outcome" players: They strike out in bunches and have low batting averages, but they compensate with extreme patience and power.
Pena, 32, is coming off a poor offensive season, failing to hit above .200 (bringing his on-base percentage down to .325) and seeing his home run total drop from a league-leading 39 in 2009 to 28 in 2010. Meanwhile, Dunn -- who turned 31 this week -- has been a model of consistency, except for a disturbing 30 percent drop in walk rate this past season.