This third grip is an awkward one to try to explain, but it moves more so then the other two grips. This would only be true with the kids that could throw it well. You can experiment with it. One of my pitchers told me that this particular pitch that I was teaching was what a lot of the college coaches are teaching their pitchers. In attending the 99 CWS (College World Series) I had asked a few of those pitchers who were competing, and sure enough, this was the one. Let's get after it?
Take a baseball and find the seams where they are closest together. Put your ring and middle finger so they are lying on each of those seams respectively. Again, refer to the picture for aid. Put your pinky and index finger on each side of the ball. Your thumb should lie underneath the ball in between your ring and middle fingers.
Now you can kind of see that this grip resembles the 'circle' or 'ok' change-up explained in the Pitching Clinic. The main differences here are:
1. The pinky rests on the side of the ball not up by the ring finger
2. The thumb and the index finger are not touching each other
3. The ball rests a little deeper into the palm of your hand
4. There is pressure underneath the ball with this grip
The pitch is thrown in the same manner as the other two types or variations of the change. This type of change can be easier to throw than the other two because of that pressure underneath the ball.