This article is part of our The Z Files series.
Be it BABIP, average exit velocity, pitcher velocity or spin rate, it's all about the component contributions. For example, take spin rate. High spin on a four-seam fastball is desirable, while low spin on a splitter is better. Say a pitcher throws each exactly half of the time. His spin rate would be the average. By means of example, throwing a 2500 rpm four-seamer and a 1500 rpm splitter would yield a 2000 rpm spin rate for this hurler. If someone else threw a 2400 rpm four-seamers and a 1500 rpm splitter, but used his fastball 60 percent of the time, his average spin rate would be 2040. Sorting by spin rate would rank the second pitcher higher, even though the first guy's spin on the pitch needing it was higher.
With MLB reportedly about to crack down on the abuse of Spider Tack and other such substances, discussion of spin rate has become all the rage. However, not everyone is breaking it down by pitch. What follows is a look at the 30 highest spin rates this season for a variety of pitches which are more effective with more rpms. The offerings include the four-seam fastball, curve, slider and cutter. Keep in mind backspin helps the four-seamer counter sinking action from gravity, while the latter three pitchers feature horizontal movement, along with vertical drop from gravity. Sinkers, two-seamers, changeups and splitters rely less on spin so they aren't included.
The spin rate and velocity of 2021's top 30 for