Relief or Reflux? An Analysis of Major League Replacement Pitching

Rich Charnigo

Statistics, CWRU

Refreshments: 3:30 - 4:00 p.m. Friday, November 19, at 327 Yost
Talk: 4:00 - 5:00 p.m. Friday, November 19, at 327 Yost.

A manager in major league baseball has the often-difficult task of deciding when and how often to switch pitchers during the course of a game. Looking at the simultaneous decline in pitching performance and increase in the use of relief pitching (and perhaps with a few contests from last season in mind), one wonders if relief pitching is being overused past the point of optimal effectiveness. We will consider how the use of relief pitching has changed over the last thirty-nine years and formulate two linear models which will relate the earned run average (a primary measure of pitching performance) to the proportion of complete games (a proxy for the amount of relief pitching). By considering a statistic designed to assess the quality of a pitching change and the proportion of pitching substitutions in 1999 contests which exceed a certain threshold value of this statistic, we will assess the overall effectiveness of relief pitching. With this finding and the results from the two aforementioned linear models, we will argue that in fact relief pitching is now contributing to the very problem which it is designed to circumvent: high scoring by the opposition.

Questions? Nidhan Choudhuri