I think you already have plenty of slugging for your park so Fielder isn't needed. If its between he and Peavy I would go Billingsley to Peavy then drop one of your cheap R-2R RP's and get Haren (5 BPHR's on his bad side) or Lowe from Glavine (a lefty with a not good card).
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I would upgrade 2nd. Iguchi to Phillips or Hudson. Right now you don't have much protection vs. LHP. Phillips will help there. Then after dropping the RP, you'll have enough to go Billingsley and Glavine >>> Vazquez/Lowe/Haren.
Dunn >>> DH with more hits. If no upgrade is available for Lewis in LF, he can leadoff vs. RHP. Taveras is sometimes available after drafts. Get him from Matthews if so. Anyone else miss berce.