Roy Halladay (PHI) struck out 14 Padres on Sunday, April 24, 2011, tying a career high. He tied San Diego in knots due to his change up. The Padres had no problem recognizing his fastball. They swung when the pitch was in the strike zone:
San Diego batters also did a good job of deciding when to take the pitch:
Roy's change up came in ten miles an hour slower than his fastball. It showed the same horizontal movement, but dipped more. The Padres got that pitch backwards:
Note the huges concentration of swings below the strike zone. Now look where the opposition was taking the pitch:
I suspect that once a batter takes one of those change ups in the heart of the strike zone, he's more likely to swing at one down further. Halladay is a master at messing up a batter's timing, changing speeds and locations. This allows him to work efficiently, going deep in games. All those skills were on display Sunday.