Seems to me the FO looked at his framing count stats instead of his framing rate stats, the former is deceptive. Last year he was a slightly above average framer, same goes for this year.
But with catchers you really have to look at the whole package.
Throwing out runners - Last year he was excellent at 44%. Career-wise he's just above average at 33%.
Blocking balls - I find he's average at best, his defense in this regard seems to be overstated.
Game calling - I have no idea about this, as it's especially difficult to quantify.
Offensively - Slightly above average. An average catcher will give you 90-95 wRC+. Martin projects at about 100 wrC+.
But of course now he's getting older. At 33 he's definitely in those declining years, especially as a catcher.