I don't know what Polanco's projected "value" is, but looking at his recent history, they're probably getting an above average defensive player, who may be slightly below league average offensively at 3B. I would worry his production may fall off by that third year, but not enough to make this a really bad signing. $6 million per year definitely doesn't seem out of line for a player of Polanco's caliber, in my opinion.