Graph of the Intermittent Time Period

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
2007 PHI 84 39 123 68% -0.26 -0.89
2008 PHI 109 34 143 76% 0.47 0.77
2009 PHI 95 37 132 72% 0.16 0.23
2010 PHI 34 10 44 77% -0.15 0.67

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.

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3 comments

  1. Nick B.

    June 15, 2010 10:09 AM

    Nice, I like it. Curious though, how much does a pitcher control the base running game? I feel like whenever Lidge allows a baserunner it always seems like that guy is taking 2nd. Lidge might not be the best example since he is in special situations…but what do you think about the topic in general?

  2. Bill Baer

    June 15, 2010 10:20 AM

    That would be interesting to study but I don’t think there would be enough data points in a given season for any meaningful conclusions to be drawn. If we study pitchers over their careers, there would be too much volatility because pitcher-catcher batteries rarely stay together for long periods of time.

    Then you could simply study pitcher-catcher batteries with a large enough sample of innings, but then that would be both selection and survivor bias.

    Relievers are notoriously bad at holding base runners. The Phillies took advantage of this against Billy Wagner and the New York Mets in that four-game sweep in August 2007.

  3. Mark

    June 15, 2010 07:45 PM

    There’s also the team philosophy issue to consider. For example the Red Sox place much greater emphasis on throwing a quality pitch and getting the guy at the plate rather than letting the runner distract that from happening. Thus several of their pitchers have not used a quick slide step that most teams implement.

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