The article that Ryan cites in today's gamelog says that baserunners have been successful in 55 of 60 attempts against Martinez.  According to Michael Wolverton's formula for stolen base runs prevented:

SBRP = 0.49*(CPO+CS)-0.16*SB,

Victor is 6.35 runs below average (unless I'm missing some information about catcher pick-offs (CPO)).  Now, that's a lot, but we can try to put it in context.

According to BP's formula, Victor, based on offense alone, is 17.4 runs above a replacement catcher.  That puts him 5th in all of baseball.

Subtracting those 6+ runs puts him around 11 runs above replacement, which is roughly 13th among catchers, or in Jojima Land.

Now, obviously this is a rough stat to start with, and most importantly, if we really want to rank catchers like this I need to add/subtract SB runs for everybody.  I don't have the time right now.

In 2003 the range for SBRP went from +8.9 runs (Bengie Molina) to -4.9 runs (Mike Lieberthal).  In 2002 it went from 9.2 (Molina) to -10.3 (Piazza, the run away noodle arm winner.  The next closest wast -3.9).

What does Victor's 55-5 suggest?  It's a ratio that will almost certainly put him at the bottom of this year's list, but you didn't need Wolverton's formula to tell you that.  Also, it's a good approximation to say that it takes Victor from being a top ML catcher to an average one.

This still supports Ryan's point, because
A) Shoppach probably won't be an average ML starting catcher, though it's not impossible.

and

B) Victor's SB-CS numbers have never been great, but they haven't been this bad.  Hopefully its a fluke, or a correctable flaw.  In the article, he seems confident that he can fix it.  I am too.

Of course, if he can play a decent 2b...