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Wednesday, August 28
How pitchers age: An investigation

By Alan Schwarz
Special to

There are zillions of ways to try to determine how pitchers are aging nowadays compared to past eras. Some of them could actually work.

Whether they tell us just how special Curt Schilling, Randy Johnson, Tom Glavine and Greg Maddux are -- four of today's best pitchers all age 35 or older -- well, that's a tricky matter. Suffice to say that their dominance, so late in their careers, is worth taking a hard look at. How rare is this? Are top pitchers lasting longer than they used to?

To make an attempt at analyzing this I chose Bill James' win shares as the method of comparison. Obviously, statistics such as wins and ERA from different ballparks and different eras (dead ball, 1930s, late '60s and today) are hopelessly hard to compare. James' Win Shares method boils down pitchers' contributions each season, no matter the era or ballpark, into one, easily comparable integer. It's a heck of a tool.

Figuring out which studies to run to highlight the accomplishments of Schilling, Johnson, Glavine and Maddux is much trickier. Here are several that I did, with some interesting results:

1. How often are there this many old, dominant pitchers?
It's possible that at season's end Schilling (35), Johnson (38), Glavine (36) and Maddux (36) will all place among baseball's top five pitchers in terms of win shares. (Boston's Derek Lowe and Pedro Martinez look to be the only interlopers.) This would be unprecedented. In fact, only once since 1900 have even three 35-and-older pitchers been in the top five: 1979, when Phil Niekro (40), Tommy John (36) and Jerry Koosman (36) did it.

Let's group the top fives by decades to see what emerges:

Decade Avg. Age Top 5 Pitchers
1900-09 28.7 3 Cy Young (3)
1910-19 28.0 3 Eddie Plank, Eddie Cicotte, Babe Adams
1920-29 30.0 6 Pete Alexander (2), Walter Johnson (2), Dazzy Vance (2)
1930-39 28.6 4 Lefty Grove (4)
1940-49 28.6 6 See comment below
1950-59 29.3 8 Warren Spahn (4), Early Wynn (2), Allie Reynolds, Virgil Trucks
1960-69 28.5 3 Warren Spahn (2), Whitey Ford, Jim Bunning
1970-79 29.0 8 Phil Niekro (3), Bob Gibson, Gaylord Perry, Luis Tiant, Tommy John, Jerry Koosman
1980-89 28.0 6 Steve Carlton (3), Tom Seaver, Joe Niekro, Bert Blyleven
1990-99 29.0 2 Roger Clemens, Randy Johnson
2000-01 32.3 4 Randy Johnson (2), Kevin Brown, Greg Maddux

Some notes:

  • It does appear as if right now is a very strong time for older pitchers. From 1982-97, not one 35-or-older pitcher placed in the top five in the win shares standings. Six have done it in the last four years.

  • I didn't list the six pitchers from the 1940s because all of them dominated during 1942-44, when most top young players were serving in World War II.

  • The best year for older pitchers ever, by this measure? 2000, when the top five -- Pedro Martinez (28), Johnson (36), Maddux (34), Glavine (34) and Brown (35) -- averaged 33.4 years old. The youngest average came in 1912, when the top five consisted of Walter Johnson (24), Joe Wood (22), Ed Walsh (31), Christy Mathewson (33) and Claude Hendrix (23).

  • You have to be a pretty darned good pitcher overall to be among the top five at age 35 or older. Of the 28 pitches who have done it, 18 are Hall of Famers or locks for enshrinement. At least three others have good shots.

    2. What happens to top pitchers after age 36?
    To get a grip on the Schilling-Johnson-Glavine-Maddux phenomenon, I used their average age (36) and took a look at all the pitchers with at least 18 win shares in their age 36 season. Poetically, there were 36 of them.

    I wanted to know how they pitched the next three years and when they ultimately retired. Breaking the 20th century into three equal eras -- so that we have somewhat significant groups while being able to locate the expansion era -- here's how they panned out:

    Years No. Pitchers Avg. WS at 36 Avg. WS 37-39 % Decrease Retirement age
    1900-33 8 25.8 15.8 38.8 42.6
    1934-1967 13 21.8 12.8 41.3 42.5
    1968-2000 15 21.1 10.5* 50.2 42.7*

    * Jamie Moyer (39) and Randy Johnson (38) still active

    Notes on this chart:

  • First of all, it's not surprising that the average win shares totals for all starters has declined over the past century -- fewer starts and complete games means fewer possible win shares. Also, I did not include the decline of Eddie Cicotte after the 1920 season, given that it was his conscience that gave out, not his arm; he was banned for his participation in the White Sox scandal.

  • It's not necessarily the largest sample, but it appears as if top, modern 36-year-old pitchers of today are not maintaining their effectiveness quite as they did in the early days. Their contributions have decreased with each passing era. I find this surprising, given modern medical advances -- rotator-cuff tears ain't what they used to be.

  • Interestingly, and relevant to the point above, it isn't as the guys are calling it quits earlier: The retirement age for these pitchers has remained virtually constant for 100 years.

    3. Are thirtysomething pitchers aging differently than they used to?
    This is an exceedingly complicated question, made worse by the fact that many of today's pitchers -- Mike Mussina, Pedro Astacio, the list is almost endless -- have yet to experience their inevitable decline. But there are a few things we can measure: for instance, how pitchers' win shares totals erode over time.

    To form a definite group, I highlighted every pitcher who reached 10 win shares at age 30 (there were 496 of them), divided them into groups of players born in different eras, and looked at how their careers wound down. Before going further, here are the basic totals of pitchers with 10 win shares or more at age 30:

    Born      Pitchers  Avg. WS
    1870-99      147     20.12	
    1900-19       80     16.84
    1920-39       84     15.60
    1940-59      117     15.54	
    1960-         68     14.31

    This is where it gets really complicated. We can't yet assess the full decline of many active pitchers because they haven't retired yet (i.e., there's no telling how Schilling will pitch, if at all, at age 38). But we can at least incorporate how those guys have performed to this point (i.e., Schilling's totals through last year, when he was 34).

    Got that? Let's look at how these pitchers aged over time -- compared to how good they were at age 30 -- both in terms of remaining active, and then their win shares totals before retirement:

    Pitchers after age 30 staying active
      --30-- --32-- --34-- --36-- --38--
    Born No. % No. % No. % No. % No. %
    1870-99 147 100 127 86.4 88 60.0 54 36.7 32 21.8
    1900-19 80 100 76 95.0 62 77.5 44 55.0 26 32.5
    1920-39 84 100 80 95.2 66 78.6 41 48.8 25 29.8
    1940-59 117 100 113 96.6 92 78.6 67 57.3 38 32.5
    1960- 68 100 68 100 -- 80.8* -- 48.9* -- 27.5*

    * Among those players who have either retired or had a chance to reach that age by 2002

    Win shares among pitchers before retirement
      --30-- --32-- --34-- --36-- --38--
    Born WS % WS % WS % WS % WS %
    1870-99 20.1 100 13.4 66.6 11.9 59.2 9.8 48.8 8.9 44.3
    1900-19 16.8 100 10.8 64.3 9.7 57.7 9.0 53.6 10.5 62.5
    1920-39 15.6 100 11.1 71.2 10.3 66.0 8.6 55.1 9.2 59.0
    1940-59 15.5 100 10.0 64.5 8.3 53.5 8.6 55.5 5.9 38.1
    1960- 14.3 100 9.3 65.0 10.5 73.4 9.5 66.4 6.4 44.8

    Having spent hour upon hour generating this data and making decisions along the way on how to handle it, I think it would be foolish, frankly, to make too many general statements about it. The samples aren't particularly large at the later ages, freak pitchers such as Warren Spahn can whack things out quite a bit, and I'm still bothered by the fact that today's active pitchers have not finished their 30s.

    Given that, there remain a few numbers to cite here:

  • Pitchers who are good at age 30 don't seem to be out of the game within two and four years as much as they used to. The staying power of those pitchers has consistently increased throughout baseball history. After that, it's a little mixed. Perhaps this suggests that modern surgery more often helps those in the first half of their 30s and before, whereas after that they don't recover quite as well -- or simply hang 'em up.

  • Pitchers born since 1960 do indeed appear to be maintaining their effectiveness better, too -- evidenced by the last line of the second chart. The percentages of those pitchers as they grow older stay closer to their age 30 performances more often than in the past.

    The 38-year-old category is lagging a bit, yes, but perhaps that's because Maddux and Glavine will hit that level in two years, Schilling in three. By that time we should have a greater idea of just how special those guys are -- as if every five days they don't give us a heck of a reminder.

    Alan Schwarz is the Senior Writer of Baseball America magazine and a regular contributor to

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