The fastball is the most basic pitch in a pitcher's arsenal, probably the first pitch anybody learns. It's the easiest to control grip is fairly simple and, unlike other pitches, allows a pitcher to maintain a good grip on the ball, and therefore, control.
But while speed is important to the pitch, the way a fastball is thrown, with two seams, four seams, etc. - is vital to giving the pitch movement. It doesn't matter how fast a fastball goes. If it goes straight as an arrow, hitters at all levels will likely catch up to it at some point.
It's all about how a pitcher holds and releases the ball. If it's released with the fingers pointed straight up, the pitch isn't likely to move much. But if the fingers are to one side or the other, the ball will get some different spin and move a little more.
There are two basic fastballs – the four-seam fastball and the two-seam fastball. And there are some specialty fastballs: The cut fastball or “cutter” and the split-finger fastball or “splitter.” And each does something different.
