Hitters Keep Getting Younger. Pitchers Stay The Same Age.

I have a confession to make. I started this article with a conclusion in mind, only to find that that conclusion was spectacularly untrue. But then I pivoted, and found something else I think is quite interesting. Is it obvious, in retrospect? I kind of think so. But I had fun doing it and learned something in the process, so I decided to write about it anyway.
I had a theory that the average catcher age, along with the average age for all the hardest defensive positions, had plummeted over the past decade, with the average DH age increasing as a counterbalance. My theory was that the universal DH allowed teams to massively alter their behavior. National League teams that had been playing older sluggers in the field could shift them down the defensive spectrum, either directly to DH or by displacing other old players to DH via a chain reaction of moving to easier defensive spots.
It’s beautiful logic, with just one problem: It’s untrue. Here’s the average seasonal age (as of July 1 each year) of catchers, shortstops, and DHs since 2002, the first year we have positional splits that allowed me to run this analysis:

The data is pretty noisy, which makes sense to me. It’s not like teams are targeting a given age; they’re just making baseball decisions about cost, team control, and production. Average age is a downstream result of a lot of decisions that are made for other reasons. But in the aggregate, the pattern I hoped to see just wasn’t there:
| Period | C | SS | DH |
|---|---|---|---|
| 2002-2010 | 29.7 | 28.0 | 31.4 |
| 2011-2020 | 28.9 | 27.1 | 31.0 |
| 2021-2025 | 28.7 | 26.7 | 29.7 |
| 2002-10 vs. 2021-25 | -1.1 | -1.3 | -1.6 |
In fact, DH has experienced the greatest decline in average age across all positions. That’s very much not what I expected. I do think that some of that is overstated. First base has had the smallest decline among positions, and I’d expect many of the displaced older hitters I mentioned in my hypothesis to end up there too. But if you average the age changes of first base and DH, they’re almost exactly the league average for position players. Clearly, the data do not support my claim. Read the rest of this entry »





