Curious how much changing the grip affects the spin on the ball. My son’s slider (supposed be a FB with a slider grip) spins counter-clockwise, when viewed from the catching position. He follows it up with the knuckle-curve (index finger only) that spins clockwise. Both pitches are thrown with the same speed, and break at the same time and about the same amount - which is not much at 46.5’ but 4" or so at 55’. The pitches appear to mirror each other.
It seems that to get this effect he may be intuitively rolling his wrist counter-clockwise on the slider and clockwise with the knuckle-curve. I’ve thought about this a lot since the last few bullpen sessions and it’s the best explanation I can think of. I woudn’t expect the amount of spin without rolling the wrist.
Is something else going on?