Injuries and ground ball pitchers

A few days ago, I linked to a post about a column Bill James had written on Bill James Online, where he suggested ground ball pitchers get injured more often then fly ball pitchers. Bill admittedly hadn't studied the issue but tossed out a list of groundball pitchers who did break down after a short period of success.

To refresh, Bill had written:

What I have never understood about ground ball pitchers, and do not understand now, is why they always get hurt. Show me an extreme ground ball pitcher, a guy with a terrific ground ball rate, and I’ll show you a guy who is going to be good for two years and then get hurt. I’m not saying this about Chien-Ming Wang and Brandon Webb; I was saying this before Chien-Ming Wang and Brandon Webb. They’re just the latest examples. Mark Fidrych. Randy Jones. Ross Grimsley. Mike Caldwell. Rick Langford. Lary Sorensen. Clyde Wright. Fritz Peterson. Dave Roberts. They’re great for two years, and then they blow up. Always.

Bill Petti of FanGraphs looked into this, using injury data back to 2002. Here's Bill P.'s analysis. He writes:

Looking at starting pitchers with ground ball rates over 48% in a given season from 2002-2012, we see that actually their odds of injury appear lower than those with less than a 48% ground ball rate (14% vs. 20%).

He later concludes:

Now, this wasn't a comprehensive study -- it was a quick look at the data on a Saturday afternoon. Others should certainly jump in and both replicate this quick look and delve into other aspects of James' hypothesis. But, for now, the initial evidence doesn't appear to support the injury risk claim.

Leaving injuries aside, keep in mind that fly ball pitchers are usually strikeout pitchers. And strikeout pitchers, in general, do have longer careers. If you have two pitchers of the same age and similar ERAs and one has a strikeout rate of 23 percent and the other has a strikeout rate of 15 percent, bet on the 23 percent guy to have the longer career.