TED WILLIAMS ON HOW LOW PITCHES ARE HARDER TO HIT. When I was a boy I was very conscious of an image of Ted Williams at bat with an image of his strike zone superimposed. The image came from his book, THE SCIENCE OF HITTING. The image of the strike zone was filled with circles representing baseballs with batting averages on them. Here is a link to the image and an article from the Hardball Times website by Josh Weinstock about the image. Ted Williams had provided the information for the image in the days before there were special strike zone cameras. The number on each baseball represented what Williams thought his batting average was on a ball in that location. For example, the balls that are colored red in the middle of the plate and belt high have a number .400 on them, representing that Williams thought that he hit .400 when he got a chance to hit pitches in those locations. The image shows that Williams thought that he hit much less well on pitches near his knees, where his batting average ranged from .230 to .280.
The image reflects that for Williams and for many other hitters, a strike at the knees was the hardest kind of pitch to hit.