Toward the end, Bill writes ...
When I talk about ground ball pitchers getting hurt, I’m not really talking about guys like Adam Wainwright and Andy Pettitte, with Ground Ball Rates around 38% or Ground Ball /Fly Ball Ratios around 5 to 4. In that context, I was talking about the guys with really extreme Ground Ball tendencies, like Chien-Ming Wang and Brandon Webb. Those guys, it seems to me, always self-destruct after a couple of years, unless their name is spelled “D-e-r-e-k-L-o-w-e”. I don’t know why.
... and he concludes, “However, many of the statements which have been made by sabermetric advocates of ground ball pitchers are also inaccurate. But I will leave it for them to clean up their own messes.”
I think that’s fair. I think some of us just sort of assumed that since home runs are bad and ground-ball pitchers tend to give up fewer home runs, then ground-ball pitchers are good. But it turns out the difference between ground-ball pitchers and fly-ball pitchers tends to be exaggerated. The only significant difference is between extreme ground-ball pitchers—of whom, there aren’t many—and fly-ball pitchers ... and Bill argues that those extreme ground-ball hitters usually get hurt after two or three years anyway.
In fairness to extreme ground-ball pitchers, Bill hasn’t offered in this essay any systematic injury analysis; just a long list of sinker-ballers who did get hurt. It’s a compelling list, to be sure. Maybe there’s something particularly dangerous about throwing sinkers that sink enough and are fast enough to fool the world’s greatest batters.