BtBS: WAR of the Ages

While [...] the average age of ballplayers is on a steady decline since 2004 or so, I was curious how Baseball-Reference’s WAR might view the changing of the tide.

I grouped position players into four (admittedly) generic age groups, 21-25, 26-30, 31-35, and 36-40 from each season since 1900 and added up all the WAR earned by each age group. (In earlier versions of this chart I did leave in the “20 and younger” group as well as the “40 and older” group, but as it turns out neither has been very relevant).

The game has gone through many changes over the years, but the 26-30 age group has generally brought home around half of all position player WAR, especially since WWII. This group essentially represents the bread and butter of batters in the league, while the 21-25 and 31-35 groups seem to have been battling for superiority over the other for nearly the entire span of baseball’s history. [...]

It is perhaps not so much of a coincidence that the brief reign of 31-35 year-olds happened to coincide with what we often refer to as the unofficial steroid era.