Since the beginning of the StatCast era, spin rate has been a popular metric among baseball fanatics. While spin rate is generally paired with higher strikeout totals, in this article we will briefly examine what spin rate is, how it effects fastballs, and how a few Brewers pitchers rank when compared to the league.
Spin rate refers to the amount of revolutions per minute (RPM) a baseball makes. This is important because the amount of spin on a pitch can affect its trajectory.
For example, if two pitchers throw a 4-seam fastball at the same velocity with the same arm angle/delivery, the pitcher whose fastball generated more RPMs will appear to have a “rising” effect for it hangs in the air longer. The “rising” phenomenon has been one reason why the MLB has generally seen an increased amount of strikeouts and fly balls.
Spin rates also have a tremendous effect on the movement on pitches. If we stick with the theme of spin rates on fastballs, two seam fastballs with higher spin rates take more to time drop and have increased arm side movement. Heavy sinking fastballs require a lower spin rate to achieve a greater downward trajectory.
There are a lot more factors to consider when determining how spin rate effects a fastballs trajectory and we are not going to dive into every factor in this article. In general, remember that all spin rates are not equal and that higher spin fastballs generally work more effectively when placed higher in the strike zone.
As for how this relates to the Brewers, since David Stearns became GM of the Brewers in 2015, acquiring high spin rate pitchers has been a theme and with good results.
The biggest increases have been seen in team strikeout totals. The 2016 Brewers pitching staff finished 28th in the league in strikeouts. In 2017 they drastically jumped up to 13th, were 9th in 2018, 10th in 2019, and 3rd best in 2020!
Taking this a step further, as a team in 2020 the Brewers had the 5th highest team 4-seam fastball spin rate at 2,360 RPMs. The Reds had the highest team 4-seam fastball spin rate at 2,489 RPMs and the league average was 2,309 RPMs.
As for individual players, in 2020 Corbin Burnes was fourth in the MLB in fastball spin rate. His cutter operated at 2,918 RPMs and his sinker 2,683 RPMs. He additionally struck out 36% of batters faced in the season, the 15th highest percentage in the MLB among starters or relievers. He was trailing starting pitchers Shane Bieber (41.1%), Tyler Glasnow (38.2),and Jacob deGrom (38.8%) in strikeout percentage.
Perhaps adding that pitching lab to the Maryvale spring training complex is also helping some of these pitchers find ways to maximize their spin rates and effectiveness on the mound.
Having high spin rate pitchers certainly does correlate with the increased team strikeout totals we have seen over the past few seasons. While spin rate is not necessarily an indicator of success, All-Star closer Josh Hader is not a high spin rate pitcher, it certainly is nice to see the Brewers valuing this metric and that these types of pitchers are having success.