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Kaplan wrote a letter to the Los Angeles Dodgers’ general
manager, Fred Claire, who was impressed with Kaplan’s concept.
“Ari came in and said, ‘I don’t think the ERA for relief
pitchers makes any sense,’” recalls Claire. “He said he wanted
to develop a formula, a statistical formula, to give a better
understanding of this situation. He asked to speak with the
pitchers and coaching staff. That is how he came up with
the research. Our pitchers, especially the starters, were very
interested in what would happen when those three hitters were
on base.”
Kaplan called his new rating Reliever Effectiveness (RE).
The stat evaluated for the first time howwell relievers come into a
game and got batters out. It was one of the first big breakthroughs
in a movement to go beyond the traditional stats that you see
on a baseball card. Reliever Effectiveness looked at a question:
When a reliever comes in with runners on base, how effective is
he at getting the runners out?
“If you are a starting pitcher,” Kaplan says, “and you leave
the game with the bases loaded, those three base runners will be
charged to you if they score. It’s completely dependent upon the
relief pitcher. So a starting pitcher’s ERA can vary ten, twenty,
or even thirty percent based off what the relief staff does.
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