Sanchez Fools Batters and Computers

Anibal Sanchez of the Florida Marlins threw the fourth low-hit game of his career on Saturday.  Sanchez raises an interesting question based on how PITCHf/x classifies his throws.  If a pitcher can fool a computer, does he also fool batters?

The following graph shows the spin of Anibal's pitches in the 2011 season:

Anibal Sanchez, spin by velocity, 2011.The big orange spots represent his fastballs.  The green spots below are the slider and change up, the slider moving toward left-handed batters, the change up toward right-handed batters.  The blue blob at the lowest point on the chart represents his curve ball.

PITCHf/x has trouble with the slider, however:

Anibal Sanchez, slider spin, 2011.Does Sanchez throw a hard and a soft slider?  Probably not:

Anibal Sanchez, slider and cut-fastball spin, 2011.There is a fastball that the computer model doesn't identify well.  It mostly looks like a cutter, but supposedly, Sanchez does not throw a cut fastball:

Sanchez throws five pitches:
A four-seam fastball that has a good deal of cutting action but doesn't sink like many other cutters.

Compare that to his four-seam and two-seam fastball, the latter called a sinker by PITCHf/x:

Anibal Sanchez, fastball spin, 2011.Notice that there is some overlap between the fastball and what is called the cutter.

So are batters fooled? They are a combined 61 for 254 on the slider-cutter combination, a .240 BA.  They hit .252 overall against Sanchez, so that combination does seem to fool them a bit.  Batters slug .378 on the pitches, versus .402 overall, so they drive these pitches less as well.  Finally, they strike out 29% of the time on the slider-cutter, 24.2% of the time overall.  The pitches that are fooling the machines are fooling the humans as well.

Comments

[andro]

So clear analyst post,