I am on the masthead, so I might as well contribute something, right?
After the 2009 season, I published catcher defense rankings at Driveline Mechanics. It was a a modified version simple methodology that Justin Inaz and others had used before. Since then, others like Mike Rogers of Bless You Boys have published versions with their own tweaks (so there will be slight differences). Moreover, in adding Dewans Plus/Minusto their player pages, FanGraphs now includes catcher's Stolen Base Runs Saved in WAR.
Still, what about some of that other stuff? Heck, I haven't contributed much here yet, but I thought that people might find it helpful, interesting, or at least humorous if I published current catcher defensive rankings (including Stolen Base Runs, Throwing Errors, Fielding Errors, and Wild Pitch/Passed Balls) semi-regularly during the season. Heck, maybe I'll even do some historical seasons if the "demand" is great enough? Sound good? No? Well, try to stop me.
Read on for the current 2010 rankings and methdology, as of today.
(Feel free to skip down to the rankings without reading all this boring stuff, but don't complain about the methodology until you've read this stuff! Then have at it.)
I went on-and-on about this stuff in last season's post at Driveline, so I won't repeat it all here (you should read that if you want to gory details.). Briefly: I don't deal with "pitch calling" because while there might be a skill here, there's no methodology for isolating it yet (that I know of) that holds up statistically.
More significantly for what I am dealing with here (the running game, pitch blocking, etc.), I acknowledge that this methodology is limited in that it can't account for the differences in catching Zack Greinke as opposed to Tim Wakefield. That's why Tom Tango's WOWY is probably the best method for catcher defense out there. Well, I'm not smart enough to do that, and it also would be difficult to do in-season (links to other WOWY approachecs can be found in Driveline post). There is also cool stuff out there (done by our own Harry Pavlidis and Dan Turkenkopf) using Pitch f/x to analyze pitch blocking.
I'm sure Dewan does stuff that make his Stolen Base Runs Saved superior to this, and ideally, we'd have more sophisticated methods all around (like the above). This is a quick, dirty, and pretty easy method using fielding numbers easily accessible at Baseball-Reference. However, I think if you examine the rankings (especially at the end of a season) and compare them to your own observations or the Fans Scouting Report, it matches up pretty well with our impressions on who the good and bad defense catchers are, with enough surprises that it isn't useless. So let me know if you think this is useful enough to update semi-regularly, although I might keep dong it, anyway!
Here are the abbrieviated formulas used. Look at the older post for the extended defenses, explanations and distinctions.
Stolen Bases/Caught Stealing: A) figure out the league rate for caught stealing; B) separate the catcher caught stealings from pitcher pickoffs; C) total the CSctch +SB to get total stolen base attempts (SBA) and then to total CSctch/total SBA for the lgCS rate; D) use the weight of .63 runs for each caught stealing, which represents the average linear weight of the caught stealing (.44 runs) plus the weight of the stolen base not achieved (.19 runs). Formula for runs above/below average: (CS - (lgCSrate) * SBA) * 0.63.
Wild pitches/passed balls: The league rate = (WPlg + PBlg)/lgPA. The linear weight for each passed ball/wild pitch is 0.28 runs. The formula for each player is ((WP + PB) - (lgWPPBrate * PA)) * -0.28.
Errors: There are two types of errors, throwing errors and fielding errors .There are separate linear weights for throwing errors (-0.48) and fielding errors (-0.75). Throwing errors: (TE - (lgTErate * PA)) * -0.48. Fielding errors: (FE - (lgFErate * PA)) * -0.75.
I round to one decimal place. That gives too much an an illusion of precision, but I wanted it so that the rankings would sort more clearly.
Keep in mind that these are "straight current value," they are "counting" stats, not rate stats. Also keep in mind the usual caveats about observed performance versus true talent!
Current Leaders and Trailers
Total Defense: The leader is Yadier Molina at +5.2 runs so far, followed by Matt Wieters at +3.8. Molina being the leader indicates we're getting at something here. So far Wieters is showing that even if his bat isn't what some thought it might be, that his throwing arm is, shall we say, "deadly accurate." Mike Napoli and Ryan Doumit are at the bottom with -4.3 and -5.0 runs, respectively.
Caught Stealing Runs: Miguel Olivo (currently #7 overall!) is throwing enough guys out to overcome his problems with pitch blocking so far, at +4.2 runs, followed by Jose Molina at +3.4. Ryan Doumit is at the bottom again at -3.9 runs, and Victor Martinez is second-to-last with -3.0.
Wild Pitches/Passed Balls: Yadier Molina (+1.8) and Carlos Ruiz (+1.5) lead, with Mike Napoli (-2.5) and Rob Johnson (-2.6) bringing up the rear. But let's face it, Johnson is in there for his bat, right?
It's too early to care about errors. Either that, or I'm too lazy.
Let the whining begin!