So let's clear up something right away. Right now the Sox have the 7th best team ERA in the AL: 3.78. Pretty bad, awful maybe. Shows how badly Buchholz has been missed, how weak the bullpen is, how mediocre the rotation is, how badly Peavy is needed.
But guess what? The two best records in the AL belong to the Rays and the Sox. The Rays, who historically have relied heavily on their pitching but right now see absolutely no need to improve their pitching, carry a team ERA of 3.76.
Everyone got that? Woebegone Sox pitching at 3.78; great Rays pitching 3.76. Oh, and don't forget that the Sox play half their games at Fenway, a pitcher's nightmare.
To me that's not enough of a difference to justify sending Iglesias away to get a pitcher whose ERA to date this year is worse that the Sox team ERA--by half a run! Peavy's is 4.28, and the Sox are at 3.78. So best case Peavy is insurance, always a good thing to have for your rotation.
But maybe the real purpose behind this trade was to get rid of Iglesias and Peavy was only a byproduct. An exaggeration? Absolutely.
But I say it to get your attention and to point out that the primary reason why the Sox were willing to let Iglesias go had to be because of his hitting. He was terrific May-June, but now seems to be coming back to earth, and the Sox see an opportunity to let a weak hitter go because in the pennant drive they are going to need as many good bats as they can muster.
I would offer that both Snyder and Holt are probably better hitters than Iglesias, especially when one can start against lefties and the other against righties. More importantly, two potentially good bats, both of whom play on the left side of the infield, are lurking at Pawtucket--Bogaerts and Middlebrooks.
As I have written elsewhere, the Sox historically (John Henry era) have worried much more about a good hitting lineup than a good fielding lineup. For big chunks of this season, the Sox led MLB in runs scored, but the Tigers now have that lead. The Sox need good hitting and will sacrifice brilliant fielding to get there. Pedroia and Ellsbury have both won gold gloves, granted, but their primary value is they lead this team in runs and hits and are at or near the top in other hitting categories.