What do you believe the effect of the spacing of the fingers is on the 4 seam fastball? I noticed a picture of Halladay on mlb.com which showed his fingers quite close together on his 4 seam grip.

Finger spacing and pressure will change ball movement on either a 4 seam or 2 seam FB. My son's coach is working with him on his 4 seamer right now and is getting him to experiment with narrower grips for more movement.

My guess is that there's also a slight effect on velocity. If you spread your fingers enough you are starting to throw a bit of a change. The question is where the tradeoff in accuracy vs. velocity and movement is. My guess is that your son's coach has got it right and that it varies with each pitcher and has to be determined through trial and error.

The farther your fingers are apart on the ball, the more velo decrease you will expereince. However, keeping the fingers too close together can result in too much tailing. It is all a matter of experimenting and finding what works best for you.

quote:

However, keeping the fingers too close together can result in too much tailing.

I don't think you can have too much tailing. You want movement on your ball. Once you get the tail, you work on learning where to start the ball to get it to end where you want.

Movement is what differentiates pitchers. Keeps the batters from hitting the ball on the sweet spot.

Having your fingers together has nothing to with movement (run, tail, sink or cut for that matter).

Movement comes from how you spin the ball.

Fingers together can produce a FB straight as a string and can also produce run, tail, sink, cut etc...

Fingers together,center cutting the ball, thumb under fingers produce the most possible velocity. Less friction on the baseball. Fingers together, ball out in my grip w/o losing control of the ball equals FB.

Spread fingers, thumb under fingers, choke the ball produce a variation of a CH (Fosh).....

Fingers meaning first and middle fingers. (power fingers)

Run, tail and sink are produced by tilting the axis of the ball or turning it over...adding to the already present pronation that occurs (like a screwball)....

tilting the axis is most common.....also it's much easier with guys that have low 3/4 arm angles to sink the ball....run and tail are included......run and tail will happen as a result of not getting over he ball.....