With Chris Snyder now rehabbing at Triple-A, it won't be long before he returns to the big-leagues, setting up an difficult decision for management - albeit one that they probably are happy to have. Snyder has been the #1 catcher for the Diamondbacks since 2007, but Miguel Montero has been a revelation since taking over in that role, after Snyder went on the DL with a back problem in the middle of June. Since taking over, Montero has been the hottest hitter on the team, and the most productive catcher in the major-leagues, with a line of .352/.373/.598, for an OPS of .971.

What will the team do when Snyder and Montero are both healthy and available? Details after the jump...

At the moment, it seems the Diamondbacks dodged - or avoided, I'm unsure which - a bullet by not trading Montero to the Red Sox in the off-season, as was seriously discussed at the time. While the reasons why  negotiations broke down are uncertain, it seems likely Arizona had a higher view of Montero's value than Boston, and the gap proved unbridgeable. If that was the case, score one for us. Know how many NL catchers with 200 PAs have a better OPS+ than Montero? That'd be one: the Braves' Brian McCann. [Full list] Miggy's 116 is miles ahead of such touted players as Russell Martin (84), Geovany Soto (89) - and even the man whom the Red Sox preferred, at a cost of $5m, Jason Varitek (100).

The case for Snyder

1. Long-term consistency. Since Montero reached the majors in 2006, Snyder has an OPS+ of 97, five points better than Montero's 92. Sure, Montero has had a great month, but two words for you there: Ryan Roberts. Montero's BABIP in the past 28 days is an unsustainable .400.
   
2. Plate discipline. While Montero has hit for both average and power slightly better than Snyder in the past four seasons, this has historically been outweighed by Snyder's much better eye. He walks about once every eight PA's; compared to Montero's 11.6. This has continued in 2009: while Montero's BA is much better than Snyder's .224, their OBP is almost identical. .357 for Montero, .354 for Snyder.
   
3. Superior defense. While difficult to measure for catchers (there's no UZR available), all the career numbers suggest Snyder is the better man with the glove:
      Caught stealing: 33% vs. 23% [2009 League average: 28%]
      Fielding percentage: .999 vs .986 [Avg: .993]
      Range factor/9: 7.80 vs. 7.53 [Avg: 7.55]

The case for Montero

1. He'a a left-handed bat. This is perhaps less an issue now than it was, with the arrival of Gerardo Parra and Josh Whitesell to semi-permanent roster spots. However, Eric Byrnes will be back, and that'll likely reduce Parra's playing time. Another LHB is always welcome.
   
2. The face of the future? We pretty much know what Snyder can do. Montero never had 50 PAs in a month before May this year. He had 81 in June, and will almost certainly get more in July, despite the break. Without a pennant race, it's a great chance to evaluate him and see whether he can be a #1 in 2010.
   
3. Practice makes perfect. The main knock on him has been defense: regular playing-time in game situations is probably the only way that will get better. There already seems to have been an improvement, particularly in his throwing - his CS% is up five points on last season to 26%, almost league average.
   

As you can tell, there are arguments in favor of both players, and I think this is likely to be reflected in what happens when Snyder returns, probably at the end of the week. Hinch will attempt to get both players into the line-up as much as possible. Snyder will likely start whenever we face a left-hander, though Montero has handled them pretty well in his career - while we're only talking about a hundred PA's, he actually has a higher BA, though with much less power [only two career HR].

My instinct is that we won't see either player traded before the deadline. Snyder's injury and Montero's hot streak make it difficult to deal them, and I think we will see the rest of the season as an evaluation period, see whether Montero is "for real". While it'd be nice to retain both men, I suspect we will see one or the other dealt during the off-season, as having a great back-up catcher is a luxury rather than a necessity. There are more obvious holes which need to be filled - in particular, second-base and probably starting pitching - and either man would be a useful chip in these areas. See IHateSouthBend's excellent review of Snyder's trade potential, as much of what is said will likely still apply off-season.

One idea which we may get resurrected is the concept of shifting Montero to third-base. This is an area into which the team dipped its toe last winter, with Miguel playing some at the position in the Venezuelan Winter League. With the departure of Felipe Lopez, second-base is once again a question-mark for 2010, so I wonder if we might see Mark Reynolds shifting there, with Montero replacing him at third and Snyder remaining the everyday catcher? If so, it's something I think should be started sooner than later - this season is basically a dead year, and I'd rather see everyone concerned use the remaining 65 games to get accustomed to their new positions.

If one or other does get traded, however, the question would still need to be addressed of a back-up catcher, which is likely more important than a sub at any other position, as they'll see more action. Since 2001, here's the median number of games played by a front-line player:
    C: 119
   1B: 144
   2B: 136
   SS: 145
   3B: 142
   LF: 137
   CF: 140
   RF: 142
That includes pinch-hit appearances, so odds are, your back-up catcher will start 50 or more games, about twice as many as at most other spots. I don't know about you, but I don't feel confident in that being Luke Carlin, a 28-year old with a career .153 batting-average in the big-leagues and .693 OPS in the minors. I'm thinking John Hester might be a better shot - he's hitting .324 for the Reno Aces, and has an OPS over .900. Aged 25, he might be the man for the job in 2010.

[All stats through Saturday night]