Baseball Crank
Covering the Front and Back Pages of the Newspaper
March 29, 2011
BASEBALL: EWSL 2011 Age and Rookie Baselines

Here's the other necessary preliminary before launching my division previews powered by Established Win Shares Levels (originally explained here): before we get to rolling out the 2011 EWSLs, I have to update the age adjustments and rookie values I use each year. These are based on the data I have gathered over the past seven seasons, and so with each passing year, one would hope they become progressively more stable and useful in evaluating the established talent base on hand for each team entering each season. As a reminder: EWSL is not a prediction system. It's a way of assessing the resources on hand.

I'll skip some more of the usual preliminaries (see last year's post) and get right to the charts:

Non-Pitchers 2010 and 2004-2010:

2010Total
Age#WSEWSL%#WSEWSL%
21-120171.17667259.01.220
22222191.15828436226.91.922
23121181101.07367812670.51.211
24162101481.41911515021162.31.292
25221781860.95717320221668.41.212
26394244650.91221324142244.71.075
27434884761.02523426052501.81.041
28293423361.01823927982745.51.019
29353973601.10322426602753.50.966
30323403970.85623025812878.20.897
31242963400.87120921962591.00.848
32252252870.78419619032386.80.797
33182091861.12416517281982.80.872
34303233690.87514614981740.30.861
3514941470.63912210251387.70.739
36141622260.717908621153.80.747
37211250.44064520814.30.639
3810781230.63449394576.50.683
39529450.64432309406.80.760
40+519340.55938261482.70.541
378398542960.92826402859830433.50.940

Pitchers 2010 and 2004-2010:

2010Total
Age#WSEWSL%#WSEWSL%
21-15130.385107356.01.304
22669332.09133265206.61.283
23646321.43862462405.81.139
2413111891.247104756661.41.143
25211611261.27816311621036.41.121
26403062881.06320413861290.21.074
27362102420.86819212481373.60.909
28271571840.85318912791362.30.939
29221481920.77117711471341.30.855
301471970.73217010211220.40.837
31281512430.6211609631226.50.785
3216931080.861120742945.50.785
33171251530.81799559786.30.711
341389851.04783462570.60.810
35972631.14361307406.20.756
36513230.56551277315.20.879
37523340.67642263325.30.808
38535291.20742282339.00.832
39211130.84629208241.30.862
40+633580.56968463652.30.710
292192921050.91620591332514762.10.903

A couple of the older-age cohorts did well, which of course is partly attributable to small sample sizes - the 33-year-old hitters had a great year, led by Aubrey Huff, Alex Gonzalez and Mark Ellis as well as better bounce-backs than projected from Travis Hafner, Troy Glaus and AJ Pierzynski. The 34-year-old pitchers were bouyed by Tim Hudson and Carl Pavano, the 35-year-olds by Hiroki Kuroda, Koji Uehara, Livan Hernandez (whose actual age remains indeterminate) and the healthy-again Chris Carpenter, and the 38 year old pitchers were carried single-handedly by Billy Wagner.

On the other hand, it was a brutally tough year for some of the age brackets here, especially the 35-and-over hitters. And as you can see, not every age cohort is uniform - the 35 year old hitters were a fairly weak group, compared to the star-studded 36-year-olds, but both lost a whole bunch of value.

The real patterns can be found in the multi-year results. What has interested me the past few years is whether there is an actual change in aging patterns since baseball started cracking down on steroids - suspensions (full list here) began in 2005 and enforcement began in earnest in 2006, but I didn't start noticing a change in the trends until after the 2008 season. So I gathered the 2004-07 results against the 2008-10 results...the comparison was somewhat inconclusive on its face, so I won't bother you with the numbers, but I noticed something that is - on reflection - not that surprising: when comparing the 2004-07 sample to the 2008-10 sample, the proportionally smaller (per-year) group tended to do better. In other words, for example, the 30-year-old hiters held 86.2% of their value in 2004-07 compared to 95.9% in 2008-10, but 30-year-olds made up 9.58% of the hitters in the earlier group and 7.53% in the later group.

When I backed the numbers out, I noticed that (excluding rookies), 23-28 year olds made up 36.88% of the hitters in my preseason depth charts in 2004-07, compared to 42.92% in 2008-10, while the proportion of 35-and-up hitters dropped off from 16.47% to 12.9%. Among the pitchers, the proportion of pitchers age 27 and under rose from 34.97% to 40.46% over the same period, while pitchers age 34 and up dropped from 19.59% to 16.46%. Put simply, as we move away from the steroid age, fewer older players are hanging on at the margins. The results are not so dramatic as to compel me to draw a conclusion, but they certainly suggest that if we're looking for a shift in aging patterns, it may crop up less in the arc of player performance than in what we don't see - more guys losing jobs or hanging it up, perhaps due to injury, who might have found ways before to prolong their productive years.

Anyway, we wrap up with the rookie adjustments, which don't really require much comment:

Rookies

Type of Player# in 2010WS in 2010# 2004-10WS 2004-10Rate
Everyday Players8826671110.77
Bench Players (Under 30)42662533.83
Bench Players (Age 30+)00430.75
Rotation Starters425321384.31
Relief Pitchers31018965.33
TOTAL1911918612016.46
Posted by Baseball Crank at 8:18 PM | Baseball 2011 • | Baseball Studies | Comments (1) | TrackBack (0)
Comments

There is no way Livan Hernandez is only 35. Is it just me or do other people feel like he's been pitching in MLB for about 25 years?

Posted by: jim at March 30, 2011 3:21 PM
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