Spin Rate is important to a fastball, with fastballs below 1800 rpm and above 2600 rpm being vastly more effective than those that ride the line in the middle. A higher spin rate fastball will appear to rise, and is more difficult to square up. ... The higher the spin rate, the better the fastball, curve or slider.

Does a fastball have backspin?

Fastballs rely on backspin. As discussed, fastballs with higher spin than the MLB average of 2,263.15 seem to "rise", as in they stay up higher than the aforementioned average spin fastballs.

Which way does a fastball spin?

A fastball has backspin, meaning that as the ball moves away from you, the leading edge (side toward the catcher) is moving upward as it spins. We define the direction using a clock face. 12:00 is the top of the clock face, so an ideal fastball, would be measured as a 12:00 spin direction.