Movement

grip, arm slot, velocity

And most importantly, spin.

All you can do is try different variations of grips and finger pressure until you find one that moves for you.

Spin...on FB, and other pitches.  In fact PG now has the ability to clock velo, and spin...I predict that spin will become a metric that will become important when evaluating pitchers.

I agree with the above, except to add that it's not just spin, but the direction of that spin. A guy throwing a FB straight over the top can have just as much spin on the ball as a low 3/4 guy, but the low 3/4 guy will have more movement because there is more sideways spin on the ball. This is where an over the top guy may have to experiment with grip pressure, to try to get more lateral spin on the ball to get the movement.

Bballman,

 

true as it relates to movement, however spin is also a determination of speed of pitch at the plate versus as measured at ball release.  The more spin, the more speed will be kept at 60'....conversely the less spin, the more velo drop at the plate.....Also could be determining factor of late movement versus early movement.

 

I have no idea:




But for JP's sake, I hope all you pitcher-parents open that secret box.

To BFS' point here I saw a PG draft profile of a HS pitcher where they discussed at length his high velocity and unusually low spin rate on his fastball.  Pitcher's spin rate was well below the MLB average.   Combination leads to a heavy sinker apparently and highly desired if it can be found.  Interesting stuff.

 

Edited to add:  Drafted in second round