Baseball Crank
Covering the Front and Back Pages of the Newspaper
March 8, 2008
BASEBALL: EWSL Rookie Adjustments, 2004-07

Last brief installment of my wrapup on Established Win Shares Levels (EWSL, explained here), this time the rookies. Rookies - players with no significant major league track record - present a unique challenge for what is intended as a system for objectively evaluating players' major league track records. As I've noted before, EWSL uses a standard arbitrary figure for all rookies. As with last season I intend to use, but sparingly, a subjective adjustment for some players, including for the occasional rookie (usually imports from Japan) in the absence of a way to apply the EWSL method to some sort of Major League Equivalency Win Shares (I don't believe they exist anywhere). Of course, the one subjective element already built into EWSL is my evaluation each spring of who looks like they have a job nailed down.

Anyway, part of the quest to make EWSL more empirical and less guesswork is that the adjustments - both the age adjustment and the rookie adjustment - get tweaked every year based on the accumulated data I have from, now, four years' worth of results. Let's look at the 2007 and cumulative results:

Type of Player# in 2007WS in 2007# 2004-07WS 2004-07Rate
Everyday Players91194248111.45
Bench Players (Under 30)1562401553.88
Bench Players (Age 30+)00221.00
Rotation Starters51914614.36
Relief Pitchers0011655.91
TOTAL292001097647.01

After 2004, I had split off the rookie bench players by age because guys who break in as bench players in their 30s generally lack upside (the same isn't true of starters, since rookie everyday players age 30 and up tend to be Japanese imports). Of course, 2007 had no rookie relievers or older rookie bench players on anyone's preseason 23-man roster anyway.

You can see that the rookie everyday players had a fine year in 2007, dragging up the average, while the starting pitchers had a bad one (and would have been a total loss without Matsuzaka).

I'll be using these figures, rounded off for this year's adjustments, but it makes sense to split the difference for the everyday players - so, 11.5 for everyday players, 4 and 1 for bench players under and over 30, 4 for starting pitchers, 6 for relievers.

Now, we'll be ready in another few days to launch the team previews.

Posted by Baseball Crank at 3:12 PM | Baseball 2008 • | Baseball Studies | Comments (0) | TrackBack (0)
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