Josh Hamilton‘s new contract covers age 32-36. So I set out to find players from the live-ball era who were comparable to Hamilton from age 26-31, and see how they had performed at age 32-36.

Before proceeding, there’s one point that I failed to state clearly in the Greinke post: I am not analyzing the financial side of Hamilton’s contract. It’s too soon to gauge the impact of the recent revenue surge on the average cost per WAR on the free market, and there are too many other value factors specific to the situation. I’m just looking at on-field performance.

Since the vast bulk of Hamilton’s value comes from swinging the lumber, I focused on OPS+ and WAR Batting Runs (Rbat).

For ages 26-31 (his entire MLB career), Hamilton has a 135 OPS+ and 128 Rbat in 3,151 PAs. His OPS+ has been pretty consistent, with four out of six years falling between 131 and 139, with one year at 170 and another at 90.

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The Comparison Group

I formed a comparison group as follows:*

• For the years 1920-2007;
• Ages 26-31 (or start of career through age 31);
• OPS+ from 130 to 140; and
• 2,500+ PAs.

There are 98 players in this group. For their years played at age 26-31, the group averaged 137 games (Hamilton 123), 577 PAs (Hamilton 525), 134 OPS+ (Hamilton 135) and 23.6 Rbat (Hamilton 21.3). Per 150 games, the group averaged 25.8 Rbat, Hamilton 26.1.

Now let’s see the group’s performance for age 32-36. Almost two-thirds (63 of 98) were active each year from 32-36, and the group averaged 4.30 seasons in that range. Only Mike Epstein and Whitey Kurowski were finished by 31.

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The Basic Comparison

Here are the group averages, first for age 26-31, then for 32-36 based on potential years played (figures in parentheses are based on actual years played), and the net change:

• Games/year: 137 … 100 (116) … Minus 27% (minus 15%)
• OPS+ (weighted): 134 … 121 … Minus 10%
• Rbat/year: 23.4 … 10.6 (12.4) … Minus 55% (minus 47%)
• Rbat/150 games: 25.6 … 15.9 (16.0) … Minus 38% (minus 37%)

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Outfielders

More than half of this group mainly played outfield in the 26-31 period (52 of 98), so let’s examine them separately. To my surprise, the OF subset was not significantly more durable or productive at 32-36 than the rest of the group. Here are the averages for the OF subset, first for age 26-31, then for 32-36 based on potential years played (figures in parentheses are based on actual years played), and the net change:

• Games/year: 136 … 101 (116) … Minus 26% (minus 15%)
• OPS+ (weighted): 138 … 123 … Minus 11%
• Rbat/year: 23.9 … 11.6 (13.2) … Minus 51% (minus 45%)
• Rbat/150 games: 26.4 … 17.2 (17.1) … Minus 35% (minus 35%)

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Power Hitters

Hamilton has averaged 33 HRs per 650 PAs. Of the comparison group, 52 of 98 averaged at least 25 HRs per 650 PAs for age 26-31. Did this subset retain more or less of its offensive value than the overall group? Here are the averages for the power-hitting subset, same format as before:

• Games/year: 137 … 96 (114) … Minus 30% (minus 17%)
• OPS+ (weighted): 134 … 119 … Minus 11%
• Rbat/year: 23.1 … 8.5 (10.1) … Minus 63% (minus 56%)
• Rbat/150 games: 25.3 … 13.3 (13.3) … Minus 47% (minus 47%)

The power hitters lost significantly more of their output than the overall group, whether measured per year or per 150 games.
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Strong Years

How many strong years did the full group produce during age 32-36? Since they averaged 23.4 Rbat for age 26-31, I calculated the percentage of years with at least 23 Rbat for each period:

• Age 26-31: 54% of years had 23+ Rbat.
• Age 32-36: 21% of potential years had 23+ Rbat (24% of actual years).

For age 32-36, the number of players with exactly N years of 23+ Rbat (number with N or more such years in parentheses):

• 5 years — 4
• 4 years — 4 (8 with 4 or more)
• 3 years — 8 (16 with 3 or more)
• 2 years — 5 (21 with 2 or more)
• 1 year — 32 (53 with 1 or more)

That’s pretty stark, no? Almost half the players in this group (45 of 98) never produced 23+ Rbat in a season from 32-36. And 79% produced no more than one such year.

(By the way, the four who reached 23+ Rbat in all five years age 32-36 were Edgar Martinez, Roberto Clemente, Bob Johnson and Charlie Gehringer. For total Rbat age 32-36, Edgar stands head, shoulders and ribcage above everyone else in this group, producing 284 Rbat — 50% more than #2 (Clemente). Only three men in MLB history produced more Rbat for 32-36 than Edgar: Babe Ruth (449), Barry Bonds (323) and Mark McGwire (300). Only 17 totaled 200+ Rbat for that age range.)

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In Conclusion

The median Rbat for the full group at age 32-36 combined was 40, or 8.0 Rbat per year. Out of 98 players, the top 18 produced at least 100 Rbat for 32-36, but there’s a sharp drop from there; #25 produced just 71 Rbat, and #30 had just 60.

Given Hamilton’s injury history and other risk factors, the most reasonable expectation would be that his age 32-36 production does not exceed the modest average of the group.

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Footnote

* I made a cursory effort to prevent WWII stats from distorting the study, but I wound up excluding only one player who met the group criteria: Nick Etten had four of his five good MLB years during the talent shortage of 1942-45, with only 1,300 PAs outside of those years; that’s just not enough to judge his true MLB ability. A few other wartime stars were left in because they had multiple good years outside of wartime, such as Bill Nicholson, Phil Cavarretta, Roy Cullenbine, Bob Johnson, Lou Boudreau, Stan Spence and Whitey Kurowski.

Spence, for example, averaged a 138 OPS+ from 1942-44, missed ’45, then averaged that same 138 while playing full-time in 1946-47. He hit well in the top minors for several years just before the war. I just don’t think that the war years — his age 27-29 — substantially distort the picture of his ability.

I wavered on Kurowski, whose first full year was ’42 and who had just 1,500 PAs outside of wartime. I ultimately left him in because his best two-year span came after the war, and it’s clear that postwar injuries (and not the leagues’ return to normal talent levels) led to his early demise.