I'm kind of fascinated by the reports on this kid's FB. Some cut, some tail, and some sink. And apparently, nobody, including him, knows which direction the ball is going. Or, even what's causing the variance. The one thing I could add to Doumit's thoughts, “I don’t know if it’s finger pressure or wrist angle or what it is, but he’s got a gift..." is this: A normal FB is thrown with index and middle finger on the seams with the thumb opposing them, roughly forming an isosceles triangle, with the ring finger second knuckle providing stability. When I switched to softball I found the movement I had, because of the shorter distance, confounded the firstbaseman. I discovered a grip change that "killed" the spin, thus reducing movement, with no real drop in velocity. All I did was change from a 3-point cradle to a 4-point cradle by moving my thumb further to the outside of the ball and adding the first knuckle of the ring finger as the 4th point. This was an accidental discovery and had more to do with the size of the ball than any mission I had. Anyhoo, if Deduno, actively or inadvertently, moves his thumb out or hits a seam with it he might "kill" some of the spin and cause apparent sink.