We can see that, after an initial surge of the extremely short in late-1880's ball as baseball became more professional and required players to be top athletes, average player height quickly reached 70 inches (5'10", aka jinaz-standard height) and then progressively have gotten taller, on average, as a group. Currently, baseball players average just shy of 74" (6'2").
No real surprises here. Thanks to some combination of improved diet, sanitation, medicine, and social programs, average human height has increased four inches in the past 100 years, and ballplayers are right on track with that increase:
WeightThis one's a bit more interesting:
Before we address that question, let's first look at one more graph
Body Mass Index
So here, we're seeing a metric that tracks both height and weight in the same number. And again, we're seeing a steady drop in BMI as the game becomes professional, a flat-lined BMI for many decades, and then a spike again once we hit 1965 babies.
The knee-jerk reaction is to claim that this matches up pretty well with the PED era. There are no clear fenceposts for when that era began and ended, but I tend to think of the steroid era running from around 1994 (the year of The Strike) until the advent of MLB's testing program in 2003. The steep part of the slope begins and ends, more or less, with players who peaked during that period of time (1992 through 2006).
The interesting thing is that it hasn't really dropped that much since MLB started its testing program. Average weight of players has decreased slightly since its peak in 1982 babies (208.7 lbs) through 1989 babies (205 lbs). Height has also dropped slightly during that time (0.3 inches), so BMI changes very little in that time. That span describes players who are currently ages 25-33. These are players that, by and large, have played their careers during a setting in which drug testing was a thing. And yet, while they've declined, we're a far cry from where we might expect to be before that spike. If the spike in weight and BMI occurred due to steroids taking over the game, and if the current testing program works well enough that steroids are now largely NOT a part of the game, we'd predict weight and BMI to return to pre-steroid levels.
My feeling is that some of this could be steroids. But I think there's two other, important factors that could be involved:
- A shift in training regimes of players: an emphasis on being bigger, stronger, and faster through weight lifting and nutrition...and for scouts to prefer bigger players.
- An influx of international talent (including lots of big guys) that push up the pool of available talent. If you have more players available to choose from, and baseball favors larger humans, you'll be able to shift up the averages by casting a larger net when selecting players.