As Otacon noted, reports from usually reliable sources i.e. not Peter Gammons, suggest we've traded our two relievers to the Braves for catcher Johnny Estrada. Villarreal has been injury-prone, with only 28 appearances since 2003, and has not returned to the form he showed in his rookie year; Cormier's arm fell off after the All-Star Break. However, Atlanta is a great place for any pitcher to go, and if they can rehabilitate their careers (and elbows) there, good luck to them. The irony is, it comes just after mlb.com posted an interview with Cormier in which he says, "A lot of guys thought we had a pretty special clubhouse." Hope you enjoyed it while you were there, Lance.
Meanwhile, we get the offensive upgrade at catcher that we desperately needed. Estrada was down a notch or two last season - though a line of .261/.303/.367 is still an awful lot better than our catchers managed - and if he returns to his 2004 form (batting .314 with 76 RBI), this could be a real steal. He was injured in June, and his replacement Brian McCann played so well, he rendered Estrada expendable in Atlanta. He's only 29 and is eligible for arbitration, so will likely get an upgrade from the $460K he was paid in 2005, but it should still lead to production comparable to that available through the free-agent market, at a lot less cost.
This is Josh Byrnes' first deal as Diamondbacks' GM, and I think that, overall, this is not a bad trade at all. Neither Cormier nor Villarreal were much more than replacement players last year. It also likely means a platoon of Estrada and Hill behind the plate: though Estrada is a switch-hitter, he has hit 45 points better over his career facing righties, while Snyder is better against left-handed pitching.