What's Wrong With Chien-Ming Wang?

(Photo by Chris McGrath/Getty Images)

"a measurement of the greatest distance between the trajectory of the pitch at any point between the release point and the front of home plate, and the straight line path from the release point and the front of home plate."

That is, I think, the break is a measure of the difference between where the ball actually ends up and where the batter might think it would end up if gravity and/or spin were not factors.

By contrast, Pitch F/X,

"is the measurement of the distance between the location of the actual pitch thrown over the plate, and the calculated location of a ball thrown by the pitcher in the same way, with no spin..."

That leaves the method of that calculation as an open question, of course, but assuming that these guys have some idea what they're doing, this seems the more relevant number for our purposes. 

The batter will assume that the pitch is going to "break" down, if only due to gravity. Even Daniel Bard's fastball, clocked between 98 and 100 MPH on Tuesday night, showed a "break" of three to five inches.

For the record, Wang's fastball/sinker seems largely unchanged, showing a break of 5-8" and a Pitch F/X of 10-14" in that complete game against the Red Sox last April. This year, in his most recent start, the fastball was just as fast, showed a typical break of 5-8" and a typical PFX of 10-13 inches.

But Wang's slider? Last year (in that particular game) its PFX averaged 4.05" (with a range of 2-7), but in his two most recent starts, it's averaged just 2.3 inches, almost half of what it once was, and often only zero or one inch.

No wonder Posada doesn't want to call for the slider. It isn't fooling anyone because it doesn't do anything, having almost the same trajectory as a pitch thrown without any spin at all, according to MLB Gameday and Pitch F/X.

For batters, this is a win-win situation. Either they swing at the occasional slider, which has hardly any spin on it, or they wait on the fastball, which is Wang's only other quality pitch.

The slider is a subtle pitch, so much so that Pitch F/X often has trouble distinguishing it from a cut-fastball and/or even a changeup. It's thrown with a sideways spin that causes it to drift laterally across the strike zone, in the opposite direction of the pitcher's throwing arm. Because it gets no horizontal assist from gravity, the slider doesn't break as much as a curveball does. 

But, it does move enough to end up several inches from where you'd expect, either out on the end of the bat or in on your hands, depending on what kind of hitter you are.  The best sliders in baseball (Carlos Marmol, Jonathan Papelbon, Francisco Rodriguez, Chad Billingsley) usually break only five to eight inches or so, though there are plenty of pitchers whose sliders sit in the four-inch range.

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