In the 15+ months since the Pirates have signed Russell Martin, there's been plenty of Pirate-related discussions about pitch-framing, its actual value, if it can truly be quantified, etc. The Pirates' trade for Chris Stewart and the subsequent immediate decision to put Stewart on the roster as the back-up catcher instead of Tony Sanchez have again started talks about pitch-framing and it's true value to a baseball team.
This morning at Baseball Prospectus, Harry Pavlidis and Dan Brooks — the two guys who've turned Brooks Baseball into such an invaluable tool for stat-oriented baseball fans — have an incredible look at the value of pitch-framing. I would strongly encourage you to check it out for yourselves and take a look at all of the different variables that have been controlled for (strike zone size, umpires, pitchers, count, etc. etc. etc.), as well as the different discussions of what pitch framing really means. The whole article is free and it's absolutely worth your time.
I know this is a topic that's always going to be controversial amongst fans; it seems borderline crazy that Russell Martin's pitch-framing and pitch-blocking (which is also mentioned in the article, to a lesser extent) was almost as valuable to the Pirates last year as Pedro Alvarez was as a whole. What I will say is this: the best publicly available sabermetric work of the past few years has come on pitch-framing, and this is a big extension of that. It's not a coincidence that when you look at the bottom of this story for the acknowledgments that two of the guys that made a ton of progress in this field (Mike Fast and Max Marchi) now work in front offices. As crazy as the total values seem, remember this: almost every pitch ends with a ball in the catcher's mitt. If there's one place in baseball in which a small difference could bear out huge value, this is that place. Even if you've been skeptical about this in the past, I think this is an article worth reading with an open mind.