When a fast ball and curve ball are mixed together it is called a slider.
which fingers on a pitcher's throwing hand controls a curve ball and a slider
A slider is thrown like a curve ball just much faster.
Curve ball, Change up, fast ball, slider, splitter.
To the batter the slider properly thrown has the batter thinking he is facing a fastball. This among other things fools the batter and he is not expecting the ball to waver in its flight to home plate. I filled in part of the discussion area to explore this pitch in more depth.
A fast ball is when the pitchers throws the ball straight at the strike zone, it doesn't curve (curve ball) or lower (slider), it goes straight ahead.
Middle Finger
A curveball falls under the general category of "breaking ball". A "breaking ball" refers to any pitch that is thrown with movement (i.e. a curveball, slider, sinker, etc.").
Click on the 'Throwing a Slider' link below to learn the mechanics of throwing a slider.
A slider is a pitch in baseball that breaks laterally and down. It is not thrown at the velocity that a fastball is thrown at, but its velocity is faster than a curve ball. The break on a slider is not as big as a curve ball. The slider is similar to a cut fastball, but will break more than a cut fastball.
4 seam fastball, 2 seam fastball, split, 12-6 curve-ball and slider
application of slider crank