Actually more than one major league pitcher back in the middle of the 20th Century were known as great slider pitchers. The ones that come to mind are Bob Feller, George Blaeholder, Early Wynn and Bob Lemon. As an aside, as a note to how effective a good slider is, Baseball great, Joe DiMaggio, a super hitter, had a terrible time hitting this pitch.
The slider is a difficult pitch to master. It also requires a developed arm strength. With that in mind, a pitcher must first be willing to practice the pitch many times before its thrown in a real game. Also, because it is hard on the arm, first master the curve ball and the fastball. When all three things are done, a pitcher is ready to use the slider in a real game.
which fingers on a pitcher's throwing hand controls a curve ball and a slider
Click on the links under the 'Related Questions' heading at the bottom of this page for instructions on throwing the pitches an MLB pitcher throws.
Middle Finger
it is a rant
if it's a right handed pitcher
For a pitcher to throw unhitable pitches. For Example Clayton Kershaw has a filthy 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.
When a fast ball and curve ball are mixed together it is called a slider.
George Uhle
four seam fastball, slider, curveball
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.