Why Are Lefties Crafty?

Last week, baseball lost former Cy Young winner Mike Flanagan. This post is not a eulogy for Flanagan. I’ll leave that to writers more skilled than myself. One of those, Joe Posnanski, wrote a tribute to Flanagan in a column entitled “The Crafty Lefty Hall of Fame.”

I’ve always been fascinated by crafty lefties, and Posnanski’s story made me wonder: why don’t we ever hear about crafty righties? Perhaps “crafty” is an adjective that — due to some old baseball tradition — is used exclusively for southpaws. The other possibility is that there just aren’t as many crafty righties. It turns out, this is one historical baseball saying that holds up under statistical analysis.

A crafty pitcher is a guy who gets by on smoke and mirrors, not raw power. I’m sure Posnanski would agree with this, in principle, but there’s one major difference between his definition of “crafty” and mine. Posnanski defines it as someone who dodges trouble despite giving up eight or more hits and getting three or fewer strikeouts in a game. To me, a crafty pitcher is someone who makes hitters look foolish despite his lack of “stuff.” He’s plenty effective, yet completely un-intimidating. In the spectrum of crafty lefties, Randy Johnson is on one end and Jaime Moyer is on the other.

Posnanski and I can differ on the semantics of craftiness. That’s not the point here. I’m here out to find out if lefties are indeed craftier than righties — or if it’s just an outdated axiom.

The data for this analysis is starting pitchers between 2002 and 2011. Apologies to Mr. Flanagan, but our pitch-velocity data only goes back that far. The sample gives us 108 pitchers and one outlier who was removed. While Tim Wakefield is certainly crafty in his own way, the knuckleballer throws a wrench into this analysis.

A scatter plot of each pitcher’s strikeout percentage and average fastball velocity shows a clear relationship between how hard a pitcher throws and how many batters he strikes out:

The definition I’m using for “crafty” are the pitchers who strike out the most batters with the least velocity. On this chart, the pitchers who are the farthest north from the trend line are the craftiest because they strike out more batters than their velocities would indicate.

Using this definition, the craftiest pitcher in baseball during this period was Tim Lincecum. Sure, he throws hard (93 FBv), but his 27% K rate is the highest in the sample — higher than Felix Hernandez, Ubaldo Jimenez, Justin Verlander and other flamethrowers. Lincecum is not the first name that comes to mind when thinking about craftiness, but The Freak is pretty crafty. (The least crafty? Carlos Silva, with his 91 FBv and 10.5% K rate.)

Lincecum is not the only crafty righty, but six of the top 10 “craftiest” pitchers are lefties. In fact, extend the list and 13 of the top 25 pitchers are southpaws — despite that only 30% of the sample is left-handed. The fact that 60% of the top 10 and 52% of the top 25 are lefties shows that, indeed, left-handed pitchers are craftier than right handed pitchers. But that begs the question: why?

The first point of interest here is that lefties, on average, throw 1.7 mph slower than right-handers. There are a number of other biological and strategic theories why this happens, and they’re probably true, at least on some level. The simple statistical answer has to do with the fact that there are simply more right-handed people in the world than left-handed people.

According to Scientific American, only 15% of the world’s population is left-handed. In theory, for every left-handed human who has the ability to throw 95 mph (one in a million, maybe?), there are eight or nine right-handed humans who can throw that hard. However, due to the strategy of baseball, there is a higher percentage of lefties in the MLB than in the general population. Teams have to reach deeper into the left-handed talent pool than they do into the right-handed one, which means there are more soft-tossing lefties.

Whatever the reason for the velocity difference, the lefties in this sample are able to get more swinging strikes and have a higher strikeout percentage than their right-handed counterparts — despite throwing almost 2 mph slower. Some of this might be explained by the platoon breakdown by hand.

While right-handed pitchers have a slight advantage when facing the same hand, the disparity between the splits for left-handed pitchers is about five-times larger. The reason behind this might be physiological — similar to the phenomenon that most left-handed hitters like the ball low and inside — or perhaps is developmental in the way lefties are coached. Any guess I have would be pure speculation. Also recall that these numbers are for starters only, so it has nothing to do with lefty specialist relievers.

The final piece of the data does little to answer our question. Right handed pitchers in the sample faced a nearly perfect 50-50 split of right-handed and left-handed hitters. The lefty pitchers faced 23% lefties and 77% righties. So, despite inferior velocity and lineups designed to minimize a platoon advantage, left-handed pitchers still posted better strikeout numbers than the right-handers did.

Crafty lefties are just one of myriad nuances that make baseball great, and the mystery as to why they exist adds to the game’s charm. Now that’s crafty.