What We Talk About When We Talk About Ground-Ball Pitchers

As I've mentioned at least three or a hundred times already, recently I was lucky enough to engage Brandon McCarthy in a public discussion, under the auspices of the first SABR Analytics Conference (excerpts and audio here). And the next day, I was part of a panel that included FanGraphs' Dave Cameron. At one point, I asked Cameron a fundamental question that, oddly (or inexcusably), had never occurred to me before: What is a ground-ball pitcher?

Dave answered and he answered well. But I wasn't really paying attention. I rarely am. So let's work through it together, just me and you ...

We know, roughly speaking, what a power hitter is. You hit 30 homers and you're a power hitter.

We know, roughly speaking, what a power pitcher is. You strike out eight or nine batters per nine innings and you're a power pitcher.

We know what a lead-off man looks like, and a good-field/no-hit shortstop. We know a crafty left-hander when we see one (raise your hand, Jamie Moyer). We know a junk-baller, and a pure hitter. We see those types of players in our minds.

Or, let me rephrase ... we see the statistics of those players in our mind's eye. Sure, we have images, too. But we can attach numbers to those images. It occurred to me that I didn't know which numbers go with ground-ball pitchers. And this was all the more obvious when I looked at Brandon McCarthy's ESPN The Magazine cover and saw this headline:

CHICKS DIG the GROUND BALL

Oh, if only that were true. Metaphorically, I mean. But I digress. Prior to interviewing McCarthy, I looked up a bunch of his numbers from last season. Given that cover and McCarthy's amazing 2011, not to mention the story inside the magazine -- McCarthy used sabermetrics to figure out he needed more ground balls and fewer home runs -- I figured he must have somehow become one of baseball's more extreme ground-ball pitchers. And he did allow only 11 home runs in 171 innings last season, which certainly is one hallmark of a real ground-ball pitcher.

But how many ground balls does it take to make a ground-ball pitcher?

For a long time, we really had no way to answer that question. Just from watching, we knew that Dan Quisenberry and Frank Linzy and Randy Jones and Mel Stottlemyre were sinker-ballers and ground-ball pitchers. You could see it. Here's Stottlemyre in his memoir, on his debut with the Yankees in 1964:

Extra adrenaline is not usually such a good thing for a sinkerballer, because overthrowing tends to make the ball straighten out, but my sinker was working nicely and the White Sox hitters kept beating it into the ground. As a result, I got 19 ground-ball outs and pitched a complete game, allowing seven hits and one walk, as we beat the White Sox 7-3.

In 1968, a National League manager said of Frank Linzy, "I like sinkerball throwers in relief, and Linzy has the best sinker around."

So, yeah. Even without the numbers, you could just tell with those guys. Just as you can tell, just by watching Derek Lowe and Brandon Webb. But all these fellows are off the charts as sinkerballers and ground-ball pitchers. What about the less-extreme cases? What does a more regular ground-ball pitcher look like? And is Brandon McCarthy really one of them?

Before I try to answer any of these questions, would you care to guess?

The obvious answer is that ground-ball pitchers get ground balls at least half the time. That is, at least half the batted balls against them are grounders.

Well, turns out that's a pretty tough standard. And maybe just about right. Last season, 94 major-league pitchers threw at least 162 innings. Only 21 of them finished with a ground-ball rate at least 50 percent.

But if you insist on classifying every pitcher as either ground-ball or fly-ball, then 50 percent is obviously far too high.

Mike Pelfrey ranked 47th among the 94 pitchers with a 45.6-percent ground-ball rate.

There's a problem with using Pelfrey's 45.6 percent as the cutoff, though ... the next guy on the list, Ryan Vogelsong, also finished with a 45.6-percent ground-ball rate. Would you be comfortable describing Pelfrey as a ground-ball pitcher and Vogelsong as a fly-ball pitcher? I certainly wouldn't be comfortable doing that.

I think we should instead classify some pitchers as ground-ball pitchers, some as fly-ball pitchers, and some as just pitchers floating around the middle, who might show slight ground-ball tendencies one season and slight fly-ball tendencies the next.

Last season, 15 pitchers finished with ground-ball rates below 40 percent; I'm comfortable with referring to them as fly-ball pitchers (at least in 2011). Which means that the majority of pitchers -- 58 of 94 -- wouldn't be classified under either heading. Which ... and I don't know about you ... I'm cool with.

Brandon McCarthy? He finished last season at 46.7 percent. So I wouldn't say he's really a ground-ball pitcher, but I also wouldn't argue if you want to suggest he's got ground-ball tendencies. He ranked 37th among the 94 qualifying pitchers. If you were choosing a cover boy to represent ground-ball pitchers -- as opposed to picking someone who visits FanGraphs and whose wife is a model -- you would probably choose someone else.

You wouldn't choose Brandon Webb, any more. He used to get his ground-ball percentage well over 60 percent, which is phenomenal; nobody topped 60 percent last season. But if you're looking for a dividing line these days, how about 55 percent? Last season, seven qualifiers topped 50 percent and most of them are somewhat famous for throwing sinkers and getting ground balls: Jake Westbrook, Derek Lowe, Charlie Morton, Tim Hudson, Jhoulys Chacin, Trevor Cahill, and Justin Masterson.

So there's our answers, I think. More than 50 percent, and you're a ground-ball pitcher. More than 55 percent and you're an extreme ground-ball pitcher (if not quite Brandon Webb).

Oh, and one more thing ... Keep an eye on that Chacin kid. He might be interesting.