When you think of hitters with good "plate discipline," who comes to mind?
Adam Dunn? Jack Cust? Manny Ramirez? Bobby Abreu?
Most guys lauded as having excellent "plate discipline" are power hitters who get pitched around often.
The statistic most often used to describe plate discipline is walks.
However, walks don't take into account the situational aspects of baseball.
For example, a pitcher is more likely to throw strikes to a slap hitter than he is to a contact hitter.
Because of the danger that power hitters present to pitchers, they get pitched around and walk more, regardless of their plate discipline.
A better way to examine plate discipline is by examining what is known as O-Swing percentage and Z-Swing percentage.
No, these aren't ridiculously complicated stats that most people don't understand.
O-Swing percentage is simply the percentage of pitches outside the strike zone that a hitter swings at. Z-Swing percentage is the percentage of pitches inside the zone that a hitter swings at.
There's also general Swing percentage, the percentage of pitches a hitter swings at.
At the bottom of the list of O-Swing percentage, Z-Swing percentage, and Swing percentage is one player.
Luis Castillo swings at the fewest pitches in the game, either inside or outside the strike zone.
He only swings at 30.6 percent of pitches, a staggeringly low number.
He is the only hitter in baseball who swings at less than half of the pitches he sees in the strike zone (47.6 percent).
While the power guys get the "disciplined hitter" tag, the slap-hitting Castillo certainly deserves it as well.
Now, guys like Dunn and Cust often get criticized for striking out a lot. Castillo takes far more pitches than either, and somehow has only struck out 19 times this season in 337 plate appearances.
His 6.8 percent strikeout rate is lowest in the majors.
The hitter who takes the most pitches in baseball strikes out the least.
That would make a lot of sense if Castillo had some sort of power, but he hasn't cleared the fences even once this season. Pitchers have no reason to do anything but pound Castillo with strikes, because the worst possible outcome is a single.
How does he do it?
Castillo has the highest Contact percentage (percentage of swings in which he makes contact) in the majors. On the rare occasion that he actually takes the bat off his shoulder, he almost always hits the ball, making contact on a whopping 94.7 percent of his swings.
Ultimately, this approach does wonders for Castillo, as he's managed to be a slightly-above-average hitter despite having an Isolated Power of just .050. He's hitting .299/.394/.349 with a .340 wOBA on the season.
Castillo's 46-19 BB/K ratio is best in the majors, and he's also stolen 11 bases.
Castillo's phenomenal batting eye and contact skills have allowed him to be an offensive plus despite packing very little sock in his bat.
So next time you think of hitters with excellent plate discipline, don't think of some hulking slugger who gets pitched around.
Think of Luis Castillo.