Doug Mirabelli and Tim Wakefield
Controlling for Abilities of Teammates: example, Doug Mirabelli
In 2000, Doug Mirabelli committed 5 passed balls in 80 games for the San Francisco Giants, good for a (teammate-unadjusted) context-neutral Component 2 winning percentage of
In 2003, Doug Mirabelli committed 14 passed balls in only 55 games for the Boston Red Sox, posting a (teammate-unadjusted) context-neutral Component 2 winning percentage of
Did Doug Mirabelli really get that much worse in just three years? Well, he did age from 29 in 2000 to 32 in 2003, so some of that could be age-related decline. But, more significantly for Mirabelli, in 2003, he was the personal catcher for knuckleballer Tim Wakefield, who had a career (context-neutral, teammate-adjusted) Component 2 winning percentage of
In order to make Player Won-Lost records meaningful as measures of player talent, it is necessary to control for the ability of one’s teammates. This is done using the Matchup Formula as described here.
The case of Doug Mirabelli, sometime personal catcher for knuckleballer Tim Wakefield, is instructive in this regard.
Doug Mirabelli’s teammate-unadjusted context-neutral Component 2 won-lost records over his career are as follows:
Outside of Boston over these years, Mirabelli’s Component 2 winning percentage was over 0.500 in five of seven seasons, with an overall winning percentage of
0.586. In contrast, Mirabelli’s Component 2 winning percentage was below 0.500 in six of his seven seasons in Boston, with an overall Component 2 winning percentage in Boston of
0.426. Overall, Mirabelli rates as a fairly poor catcher at preventing wild pitches and passed balls, with an overall Component 2 winning percentage of
When Mirabelli’s Component 2 won-lost record is adjusted to control for the pitchers who Mirabelli caught, however, the results are the following:
Adjusting for the pitchers he caught, Doug Mirabelli turns out to have been slightly above average at preventing wild pitches and passed balls through his career. Outside of Boston over these years, Mirabelli’s Component 2 winning percentage remains fairly consistent after adjusting for his teammates, at
0.576. With Boston, on the other hand, Mirabelli’s combined Component 2 winning percentage improves dramatically from
0.426 unadjusted to
In words, adjusting for Mirabelli’s teammates brings his Component 2 winning percentages closer together over time. Mathematically, the standard deviation of Mirabelli’s winning percentages falls from
0.110 unadjusted – i.e., Mirabelli’s Component 2 winning percentages fell mostly in a range of
0.470 +/- 0.110 (0.360 - 0.580) – to
0.090 adjusted – i.e., Mirabelli’s Component 2 winning percentages range from
0.426 to 0.606 (0.516 +/- 0.090).
Mirabelli was still a bit worse in Boston than elsewhere. Of course, outside of one month in 2006 in San Diego, his career outside of Boston came at ages 25 – 30, while his Boston career was from ages 30 – 36. So based on age alone, we would have expected him to probably be a little less agile at blocking would-be wild pitches in Boston than in San Francisco and Texas.
It seems clear to me that the latter set of numbers more accurately reflect Doug Mirabelli’s ability to prevent wild pitches and passed balls.
All articles are written so that they pull data directly from the most recent version of the Player won-lost database. Hence, any numbers cited within these articles should automatically incorporate the most recent update to Player won-lost records. In some cases, however, the accompanying text may have been written based on previous versions of Player won-lost records. I apologize if this results in non-sensical text in any cases.
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