- First, this data is pretty easy to come by. Baseball-Reference.com's Batting and Pitching Encyclopedia pages have it.
- In the earliest days of baseball, it was truly a young man's game, with the average age of pitchers even falling below 22 in 1878. Over the last 30 years of the 19th century, ages increased gradually, presumably as the game grew and the talent pool became increasingly larger.
- I am not sure why the ages then dropped from 1908 to 1913 so much, but it may have simply been a "correction" for more men getting involved in baseball, meaning a weeding out of some of the older players who couldn't keep up with the 25-27 year-olds as the overall level of competition became better.
- In 1918 there is a sudden jump up in age, presumably as some younger players left to fight in World War I. Interestingly, though, the age didn't drop back down when the war ended but continued to rise.
- The next big jump up comes in 1943 as players left to fight in World War II. The age came back down as players returned. There is another jump, for pitchers at least, for the Korean War in 1952 and 1953.
- I have no explanation for the steady rise from 1977-1983. Expansion might be part of it, but that alone wouldn't cause a steady rise over so many years.
- Finally, when the Steroids Era arrived, the average age crept up. It finally crept back down starting in 2004-2005, when the wave of older players from that era started retiring (Just check out this year's and next year's Hall of Fame ballots...)
- Note that batters were much older than pitchers just about every year until 1923, when both groups were 28.3 years old on average. After that, pitchers were older every year until 1955. The ages tracked closely until the Steroids Era, when batters got older again.
Average age of pitchers and batters across all of MLB historyPosted by Andy
at 8:57 AM