Some hurlers pitch backwards; they throw off-speed pitches in fastball counts and vice versa. Rookie Dustin Ackely of the Seattle Mariners hits backwards.
Most pitchers use a change up as an out pitch. They train a batter's pattern recognition software to learn a fastball motion. Once the hitter sees the fastball enough, the pitcher unleashes the change up. The best throw the pitch with the same motion and arm speed, but drop the speed of the ball with their grip. The batter swings early and misses, or hits the ball weakly. In the majors this season, batters own a .339 weighted OBA (wOBA) on the fastball, .290 on the changeup.
So far, Ackely hits the change much better:
You can really see the reversal in the strikeout and home run numbers. Fast pitches help batters hit home runs. Dustin has yet to take a fast ball deep. Change ups are supposed to fool batters into striking out, but Ackely doesn't get fooled by the pitch.
These numbers, of course, are based on small sample sizes. If they hold up, however, it won't be good news for Dustin. If pitchers discover they can just pump fastballs by him, they'll be happy to blow him away with heat.