Pitchers with high ground-ball rates have been shown to age worse than the average MLB pitcher. The study comes from Eno Sarris at FanGraphs, with help from Jeff Zimmermann, and focuses on the aging curve for pitchers with a ground-ball rate of 50% or higher.
The basic premise that led to the article was a Bill James "rant" about how very few great pitchers were ground-ball pitchers, and also that ground-ball pitchers suffer more injuries and are "never" good for long. The "never" was easily dismissed as hyperbole and the "more injuries" claim was seemingly debunked by examining DL stints and games missed due to injury. This new study came at it from a different angle though, and while ground-ball pitchers might not suffer more injuries serious enough to lead to DL trips, they become ineffective more quickly and are more likely to be out of baseball at a younger age.
The aging difference doesn't show up while pitchers are still in their 20s, but at age 30, the two groups (ground-ball pitchers and all pitchers) begin to separate, and the gap grows as they continue to age. Looking at qualified starting pitchers who were 28 or older last season, there are nine who had a ground-ball rate of 50% or higher. Felix Hernandez and Jake Arrieta, two of the best pitchers in baseball, were both at 56.2%. Most notably for Tribe fans, Carlos Carrasco is also one of those nine pitchers, at 51.2%.
Carrasco turns 29 later this month, so if you were going strictly by the study's findings, you could expect him to remain at only a normal risk for decline in 2016, but a greater risk in 2017 and beyond. Obviously not every ground-ball pitcher is going to blow up when they turn 30, and Carrasco could be among those who bucks the trend, but the study finds that of those nine pitchers from last season, odds are only 2 or 3 of them will still be pitching four years from now, which is a scary thought.