Back in April, we took a look at every pitcher who had thrown the slider more than 40% of the time during the past three years. The results weren’t pretty. The “Slider Group” was more likely to have major surgery on their arm or on their shoulder than the general pitching population. They also hit the DL more than average. To say the least, the pitch seems stressful.
Since the slider cutoff was so high, and the innings minimum non-existent, our 25-pitcher sample was made up entirely of relievers. Now with Brett Anderson reporting some general elbow soreness and a hefty slider percentage (41.1%), it seems like a natural time to ask the follow-up question: Do we see the same propensity for injury, both major and minor, among starters who favor the slidepiece? Did that pitch gobble up Anderson’s elbow ligaments like they were so many miniature hamburgers?
Though some commenters favored using raw pitch numbers to compare pitchers, that approach has pitfalls of its’ own. If we counted pitches, we might run into a sample that eliminated the unhealthiest pitchers. And yet their use of the slider might still have had something to do with that failing health. So instead, we’ll continue using percentages but we’ll throw an innings limit in there in order to try to hone in on starters. Since we’re mostly trying to compare Anderson to his peers, we’ll use 200 innings (since the beginning of the 2009 season) as a cutoff. It’s random, but it helps us find comparable starters who have pitched over the same time frame and used the slider about as much.
Our Starter Slider Group:
|Starter Slider Group||55.69%||91.6||28.04%||84.1||1|
That the starters here throw faster (91.6 MPH fastballs to 89.9 MPH) and throw more fastballs (55.7% fastballs to 46.3%) than our reliever group isn’t extremely interesting for this discussion. They probably only throw harder because of the size of this sample, most likely. Also somewhat likely is the possibility that they are starters because their fastballs are better than the fastballs in the reliever-only group. Starters are picked to be starters, generally, because their pitching mix is more diverse and they have more effective pitches. So, since they’re more likely to have a larger arsenal, it makes sense that they would throw fewer sliders than the relievers (28% sliders to 47.3%).
But the juicy findings are in the last column. These 25 pitchers averaged one stint on the DL since the beginning of the 2009 season. Jeff Zimmerman found that the typical veteran starter was 39% likely to hit the DL in a given year. Since these pitchers have played about 2.35 seasons on average since then, they were 42.5% likely to hit the DL during a season in the sample. Not quite as an extreme a difference from the general pitching population as our relievers showed us.
Over their careers, this group has had Tommy John surgery four times. That’s 16% of the sample. Again, that number is larger than the national rate of occurrence (10.7%), but not as far gone as the 20% in the reliever sample. Lastly, 17 of these 25 pitchers have either hit the DL for an extended bout of pain in their elbow or in their shoulder. Pitchers get hurt easily, but these pitchers seem to get hurt more often.
Brett Anderson has thrown his slider 33.7% of the time. That’s the fourth-most among starters with at least 200 innings since 2009. During that period, he’s also hit the DL twice for elbow problems. These days, his velocity is down a bit and he’s complaining of soreness in the joint. The general health of the other slider-heavy pitchers on this list suggests that Anderson’s upcoming appointment with the doctor is a significant one.