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Monday, November 14, 2011
Replacement-level: playing time
A reader asked about using plate appearances (PA) instead of innings played (IP) as the playing time component in replacement level.
Notably, leadoff hitters earn more value than a 9th place hitter, even if both are equal as hitters. Since replacement level is roughly .003 wins per plate appearance, and the gap between the number of PA for a 1st and 9th place hitter is 8/9 x 162 = 144 PA, that’s roughly 0.45 wins extra the leadoff hitter gets.
I agree, and PA is being used only because of lack of IP data being available. And general laziness. I think Rally accounts for this rWAR.(*)
(*) By the way, who started calling it bWAR? It’s rWAR.
The only issue is what to do with PH and DH. What you can do for them (and for all of them) is to look at fractions of PA for the lineup slot they are in. So, if they have 4 PA for the day, and their lineup slot came to the plate 5 times, then you give them 80% of a game.
Of course, we should do the same for innings played, so if they played 8 innings out of 9, that’s 89% of a game.
Generally speaking, a non-pitcher’s value is generally about 62.5% offense and 37.5% fielding. So in the above case, I’d credit the player with 83% of a game.
So, if you care about every 0.1 or 0.2 wins to give out, use this method instead.