Age and EWSL, 2004-05 Combined

Revisiting a topic I looked at here and here following the 2004 season, I now have two years of data to work from in evaluating how players tend to perform at each age relative to their adjusted Established Win Shares Levels (EWSLs are explained here). I went back and broke out the totals for 2004 and 2005 into pitchers and non-pitchers. Here are the results, which you may find interesting but which I’m recording here mainly for reference as the backup for the revised age adjustments I’ll be using for the 2006 EWSL:
Non-Pitchers:

Age # WS EWSL %
21- 4 33 34 0.878
22 11 204 90 2.267
23 13 157 112.433 1.396
24 28 335 261.566 1.281
25 46 548 437.8 1.252
26 63 664 576.1 1.153
27 68 746 744.833 1.002
28 86 1127 1031.232 1.093
29 74 857 943.8 0.908
30 67 779 808.366 0.964
31 59 588 747.366 0.787
32 57 554 627.833 0.882
33 53 568 654.433 0.868
34 41 386 415.833 0.928
35 41 278 384 0.724
36 26 277 353.333 0.784
37 24 213 301.166 0.707
38 14 132 163 0.810
39 10 127 157 0.809
40+ 9 60 138 0.435

As I’ve explained before, the nature of any established performance level will exaggerate the upward and downward trajectory of player aging, since a 25-year-old is still being partly compared to his 22-year-old self, while a 35-year-old is still being partly compared to his 32-year-old self. Even so, the dramatic nature of the effects of aging is still apparent, as the rapid pace of improvement stalls out at 27, while the sharp downward spiral begins at 31 and never really lets up. And you can see, as well, how the results of this play out in the expanding and then contracting number of players of each age holding regular jobs.
The youngest age shows disappointments mainly because of guys like BJ Upton who get projected as possible contributors before the season and then stay the full year in the minors. The 40-year-old-and-up crowd looked much better in 2004 than 2005, because Barry Bonds joined their number with a huge raw EWSL and ran off the bridge.
Pitchers:

Age # WS EWSL %
21- 5 23 17 1.353
22 11 92 63.4 1.451
23 17 141 138.93 1.015
24 25 170 149.1 1.140
25 34 273 218.63 1.249
26 59 376 370.5 1.015
27 58 362 388.66 0.931
28 59 415 378.4 1.097
29 54 350 401.766 0.871
30 43 279 310.13 0.800
31 43 261 333 0.784
32 43 243 353.8 0.687
33 31 180 239.8 0.751
34 25 113 157.166 0.719
35 21 78 143.666 0.543
36 14 77 93 0.828
37 17 123 132.833 0.926
38 17 126 163.166 0.772
39 13 80 106.833 0.749
40+ 13 146 153.666 0.950

If anything, the aging pattern on the pitchers is more severe, with the rapid growth phase ending by age 26 and steep decline setting in at 29. This is undoubtedly due in good part to injuries as well as to the number of pitchers who only have one decent run around the league. The 40+ pitchers, of course, include a disproportionate number of Clemens and Randy Johnson seasons, and may not be informative for lesser mortals even of the Tom Glavine variety.
One thing is clear, though: never, ever, ever underestimate the power of the tides of age over players in their 30s.

3 thoughts on “Age and EWSL, 2004-05 Combined”

  1. The Bonds question that no one has answered yet, is: Just what has he found that the others have not?
    Or perhaps, another question: Just what is it that makes some people (in this case, baseball players) so much better than their peers. Bonds, like Cobb, Mantle, Ruth, Mays and few others, these players rose far above their contemporaries. Are they so superior to start with, that an equal enhancement of Bonds made him so much better (however, much of the Bonds mystique is the amount of walks he took, which shows how much fear he did generate, also, perhaps how much over-exageration generated by that fear). If Mantle had juiced up as much (allegedly), would his numbers also be ever higher?
    I don’t know. The only athelete at that high a level I watched close up was John McEnroe. He was tuning up for the Open while I was playing with my coach (another story about pro sports, interesting, but for another time). He played two on one. The two was his doubles partner Peter Macnamara, and a teaching pro against Mac. I watched, and they were losing. Two pros against one, and Mac looked like he was moving in slow motion; almost not trying, yet he was winning. He was clearly a superior physical specimen. He had the uncanny abilitly to know where the shot three shots down the road was going to go, you could tell, plus he simply moved differently.Gretzky was like that. So was Magic Johnson. What could he have done had his speed been chemically enhanced?

  2. I think the question is answered: He found a unique discipline for taking unprecedented amounts of steroids in combinations and cycles far beyond what anyone else was doing. Bonds pre-1999 was one of the best (maybe the best) players in baseball but he did not tower over the league the way he did from 1999-2004. Certainly he was one of a unique group before the doping began but he was not out on an island of singular greatness. Gretzky operated in a sphere unto his own that no one ever entered or has entered since (the next time someone wins 8 consecutive MVPs you let me know).

  3. I’m curious about one thing — how do these numbers hold up if EWSL is normalized for 162 games? Or is it?
    What I imagine is that both very young and aging players are going to play less than full seasons — young players because they are more likely to be platooned; aging players because they get rest days, or go on the DL more often for minor injuries.
    If normalized for 162 games, is the average decline as severe?

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