One of the hot topics that has been dominating talk at a few of the baseball message boards that I visit is this:
Right-handed batters have a fairly consistent platoon advantage against left-handed pitchers. On average, righties have an OPS that is 8% higher against left-handed pitchers than right-handed pitchers.
Here's the thing, though:
At the major-league level, no matter who the right-handed batter is, and no matter what they've done in the past against left-handed pitchers, the odds are that they will remain approximately 8% better against lefties than righties.
Why does this matter?
Well, for one, some batters have a reputation for being "lefty-mashers" - guys that just kill left handed pitching. Frank Thomas, Reggie Sanders, Brian Jordan, Phil Nevin, etc. all have much higher career OPS against lefties than righties (more than 8% higher, that is.) So why is the smart money on betting that everyone will do equally better?
Well, a few things. Sample size. The average right-handed batter only gets about 100-150 AB's a year against lefties - some a lot less than that. That's not a whole lot, really. You're going to get a lot of variance. There are also a TON of right-handed batters in baseball. Every year, a few will do much better than normal against lefties, and a few will do much worse than normal. But you have to think of these as outliers - on either end of an imaginary Bell Curve. Even though every year there are consistent outliers - guys that are always on one end or the other of the curve - this, too, is not completely unexpected. Other researchers have crunched the numbers, and it's right. It works.
So, what does it mean?
Basically, lefty-mashers don't really exist. It's a myth, like clutch hitting, Derek Jeter's defense, and eating too many breadsticks at Fazoli's. And that is all.