Posted by Andy on September 17, 2010
How old is the typical DH? The commonly-accepted answer is that DHs are older than average because teams tend to stick an aging guy who can't play the field so well at that spot.
Generally, that old answer is still true, but the picture has been changing over the years. Click through for some data and discussion.
To answer this question, I went through every year since 1973 and found the average age of DHs in each season. I decided to set 50 games at DH as the cutoff, mainly to avoid collecting a lot of players who were used as injury fill-ins at DH. The goal of this study is to look at the philosophy of the DH and which players teams put as the starter at that position.
For each year, I found the weighted average of the DHs with at least 50 games, using teach player's plate appearances as the factor. For example, here are the guys to play at least 50 games at DH in 2009:
My averaging system is far from perfect. Many of these guys played positions other than DH but I am using their season totals. It's not a bad approximation, and after all I'm just trying to get a general sense. If you multiply each guy's age above by his plate appearances, then divide the total of those numbers by the total number of plate appearances, you come up with an average age of 31.8 years for 2009.
Here, then are all the average ages going back to 1973:
The red line is the average age of all American League batters for the same year. I got those numbers from the AL Batting Encyclopedia page. There are a lot of cool things to notice about the above graph:
- You can immediately see that, yes, DH's have always been older than the average AL batter, and continue to be to this day. Also keep in mind that the average number includes the DHs themselves, meaning that the average age of everybody except DHs is even lower.
- You can also immediately see why the DH is thought of as the old man position. In its first few years, quite a few older players were put at DH (including Billy Williams, Frank Robinson, Hank Aaron, Al Kaline, Rico Carty, and Orlando Cepeda) plus 3 guys were DHs who qualified by my criteria above in each of the first 3 years (1973-1975): Tony Oliva, Deron Johnson, and Tommy Davis, and these guys were all 36 in 1975.
- Then, from 1980 to 1986, the reputation of DH being an old man position really soared as the average age climbed higher and higher each successive season. Maintstays at the DH during this period included Hal McRae, Andre Thornton, Don Baylor, and Cliff Johnson. These guys played DH each year and got one year older each year too.
- Note, though, that we've seen the opposite happen since then. From 1998 to 2002, the average DH age dropped each year, even as the overall average player age was higher than in the 1970s.
- In 2006, the average DH age went way up as Jim Thome joined the White Sox, coming from the NL and joining the DH ranks. Rondell White also played 50 games at DH for the first time, as did Matt Stairs. Add in some other older players (Tim Salmon, 37, and Phil Nevin, Javy Lopez, Jason Giambi, and Carl Everett, all 35) and the result is a big spike that year.
- Overall, the large amount of noise in the DH line is due to the fact that a fairly small number of players (around 10) qualify each year. Individual player retirements or position changes show up on this sort of graph.
I mentioned above how the underlying average age of players has been increasing. That's what the red line above shows. It's interesting, then, the plot the ratio of the two so we can see how much higher than overall average age the age of the DHs is.
This shows us that the average age of DHs peaked in 1975, when they were about 23% older than the average AL batter. Even though the average DH age was, in raw numbers, higher in 1986 and 1994, the DHs in those years were not even 20% older than the average AL batter.
In 2009, DHs were just 9% older than average AL batters. That's not the lowest in history--it was just about 7% in 1977. But the black trendline I added above shows that generally speaking, DHs are getting younger and younger relative to the average AL batter (but are still significantly older.) At the rate of that black line, it would still take more than 100 years for the DH age to reach the overall average age. I'm willing to bet that changes in the game will have a lot more to do with what happens than the general trend we've seen so far.