This grip allows the pitcher to quickly and easily move to any of his pitch grips with little movement, and smooth actions. Over time, a pitcher will find a grip that is most comfortable (somewhere in between their two or three pitches) which will allow them to grip each of their pitches with minimal movement. They can avoid any major movement of the wrist and forearm, and begin each pitch sequence with the same grip.
The random grip results from not adjusting the ball after receiving it from the catcher. There will be no consistency to how, and how much the ball is rotated or adjusted with regard to any single pitch. Instead, for each pitch, the pitcher will grab the ball, recognize the grip, and adjust accordingly. Sometimes there will be a quick adjustment, and other times the pitcher will need to rotate the ball several times. Just be careful that your actions don't signal the pitch as you grip the ball (i.e. digging for a curveball).
Problem No. 3: Finger Pointer
This problem arises when a pitcher extends his index finger when gripping for specific pitches. Most commonly associated with the digging motion of grabbing a curveball grip, a player will unknowingly lift their index finger only when they dig. It sounds silly, but athletes will often do this without realizing that they are moving their finger at all.
Solution: Instruct your pitchers to keep their index finger inside the glove while pitching. Pitchers that use either an open-back glove--or a closed-back glove with a finger hole--should be taught to keep their fingers inside the glove while on the mound.
Remember, opposing teams don't need to pick all your pitches to be effective. An offense can gain great advantage by only knowing when one of your three pitches is going to be thrown. This can be the difference between strike three on the inside corner, and a batter turning on the ball and ripping a ball down the line. The problems that offenses look for are tiny movements, and can be avoided by small, common sense, adjustments.