Two graphs in two days? I must be on a roll. Actually, I meant to post this a few days ago but never got around to it. Last week at Baseball Daily Digest, I attempted to quantify the throwing arm of St. Louis Cardinals catcher Yadier Molina by comparing their opponents’ base-stealing aggressiveness and success to the rest of Major League Baseball. The results were staggering — Molina is one hell of a catcher, as the charts and tables in the article illustrate.
So I decided to do the same for Carlos Ruiz, who is regarded as a good pitch-blocker and a great game-caller. You don’t hear much about his arm and there’s a reason for that: it’s average. Only in 2007 did he nab runners significantly above the National League average, 31% to 25%. Since 2008, he has been a few percentage points below average.
The following chart depicts a scatterplot with data going back to 2005. On the X-axis (horizontal), each teams’ opponents’ stolen base attempts — a.k.a. aggressiveness — is charted. Markers towards the left depict passivity. On the Y-axis (vertical), each teams’ opponents’ stolen base success is charted. Markers towards the bottom depict base running failure. So the further southwest the markers are, the better for the catchers.
Everything has been normalized into a z-score, which tells you how many standard deviations from the mean a particular data point lies. For instance, last year, opponents attempted to steal 132 times against the Phillies’ catchers. The average stolen base attempts against in the National League in 2009 was 128. By subtracting the league average from the Phillies’ number, and then dividing that difference by the standard deviation (25), we come up with our z-score of 0.16. That simply tells us that opposing teams ran against Ruiz and the Phillies at about an average rate.
|Year||Team||SB||CS||SBA||SB%||SBA Z||SB% Z|
Numbers are accurate as of a day or two prior to the publishing of the Molina article on June 7.
Obviously, the methodology is not perfect as I use team totals instead of individual totals. This is simply because I lack database skills and it is too time-consuming to piece together data on all catchers over the last five or so years. Overall, however, this more than does the job at putting a catcher’s ability to control the running game into perspective.
Things Ruiz is good at doing: blocking pitches in the dirt, calling games.
Things Ruiz is average at doing: hitting, controlling the running game.
Things Ruiz is bad at doing: resisting ice cream.