Here are two players' career pitching stats. Both players were 27 years old last season.
IP SO BB ERA WHIP ERA+
Player A 815.3 575 363 4.65 1.44 96
Player B 798.0 507 280 4.79 1.46 97
Player A has more strikeouts, but also more walks. Now if I told you that Player A spent his entire career in one of the best pitchers parks in baseball, and Player B spent almost two years pitching in Coors Field, which player would you say is better?
I dunno either. Seems to me that they're pretty much the same guy. Except perhaps that Player A is right-handed, and a free agent, and Player B is left-handed, and has a year left before free agency.
Yesterday, I objected to placing Kennedy in the rotation. Obviously, I'm an idiot, and Billy Beane is a genius. The A's have a pitcher worth $55 million! You don't waste pitchers worth $55 million (even if you're only paying them about $4 million) by having them get a couple of outs in the sixth inning every few days. You get every penny of your $55 million worth, and pitch them as many innings as possible!