Take your pick. First, from Fox Sports :
D-backs look to deal Snyder. Arizona is ready to make a change at catcher. The Diamondbacks are trying to trade Chris Snyder, this season's starter, to clear the way for Miguel Montero. If the Diamondbacks are successful, they would bring in a low-paid veteran such as Gregg Zaun as the combination backup-mentor to the 25-year-old Montero.
On the other hand, from Nick Piecoro :
We’re hearing that’s not true. Another team called recently about Snyder, the Diamondbacks’ listened, but nothing ended up happening. It still sounds much more likely they move Miguel Montero. In fact, rather than deal Snyder, there are indications they will discuss a long-term deal with him.
Time will tell, though dealing Snyder perhaps makes some sense on a number of levels. His trade value is certainly higher, and Montero's left-handed bat, on a full-time basis, would be an asset to a line-up which skews severely to the right. Snyder will also cost a lot more money: he earned $1.85m in 2008 in his first year of arbitration-eligibility, and would likely be up to perhaps somewhere around three million in 2009. Compare Montero, who will still be at league-minimum, though some of the savings would likely have to go towards paying the veteran replacement.
On the other hand, what would the point be dropping Snyder, to sign Zaun? He earned $3.75m last year, so would be little if any cheaper as a back-up, than Snyder as a starter. There's also the matter of Zaun's name cropping up in the Mitchell Report, an allegation which Zaun attempted to defuse with a convoluted tale involving a bet with Jason Grimsley - I kid you not. Two months after his name surfaced, the explanation Zaun came up with was, "He owed Grimsley $500 -- possibly for losing a bet on a basketball game -- and he gave the check to the pitcher without penning Grimsley's name on the document. From there, it's Zaun's belief that Grimsley scribbled Radomski's name on the check and used it to buy steroids." Yeah...
More likely in the event of Snyder being traded would be some of the other free-agent catchers who might be available for a backup role this winter [I've left off ones like Ivan Rodriguez and Jason Varitek, who are presumably not looking for a secondary position at the moment]. The list has their name, age as of next season, 2008 OPS+ and 2008 salary.
Rod Barajas, 33, 86, $1.2m
Henry Blanco, 37, 83, $3.175m
Johnny Estrada, 33, -2, $1.25m
Toby Hall, 33, 66, $1.75m
Adam Melhuse, 37, 11, $750K
Mike Redmond, 38, 80, $950K
Javier Valentin, 33, 89, $1.35m
Vance Wilson, 34, 90, $950K
To give you some idea of the current market, another possible contender, David Ross [32, 88] was signed to a two-year, $3m deal by the Atlanta Braves. Most of the names on the list above would seem serviceable, though I can't see Estrada ever coming back to Arizona, for a number of reasons. But someone like Barajas, Redmond, Valentin or Wilson would seem more than suitable, if they needed to give Montero the odd day-off here or there.
The most obvious downside of this move would be defensively, apparent in an immediate form from the 79.4% of base-stealers who proved successful against Montero, compared to 69.0% for Snyder. Another question would be, Is Montero ready to become a full-time catcher? His career high at the position is only 108 games, back in 2006 and all but five of those were in the minors. Last year, he had only 404 innings behind the plate, plus less than ten games for the Sidewinders: Snyder probably came close to doubling that figure, even with his unfortunate injury. It'd be quite a step-up to make for Montero.