St. Louis Cardinals: A Look at Kevin Siegrist’s Development

Kevin Siegrist introduced a new curveball in 2016.

The biggest change in Kevin Siegrist’s curveball location in 2016 results from the implementation of an entirely new pitch as the St. Louis Cardinals reliever adapted his approach against LHH.

Prior to the 2016 season, Siegrist’s breaking ball had never averaged below 80 MPH. He threw a hard curveball that sacrificed vertical movement for velocity and late drop (in fact, the pitch was sometimes recognized as a slider instead of a curveball). While Siegrist struggled to locate this pitch in his first two seasons, he seemed to have found an answer in 2015.

However, Siegrist scrapped his hard curveball following the 2015 season for a slower, more vertically oriented curveball. He was able to make the transition while maintaining an effective release point and tight location core just below the strike zone, as was shown by his 2016 curveball heat map. Below are Siegrist’s curveball velocities and movement by year:

By slowing down his curveball, Siegrist added more than 20 inches of vertical movement. While more vertical movement does not necessarily equate to a better pitch, a few indicators suggest Siegrist’s curveball last year was significantly improved.

Firstly, by altering his curveball, Siegrist aligned his curveball release point with his fastball release point. In 2016, there was no noticeable difference in release point between the two pitches, which makes the curveball much harder to distinguish from the fastball. Thus, the curve was much more deceptive in 2016 than it ever had been.

Siegrist’s new curveball induced significantly more whiffs than his harder curveball had previously, with LHH Whiff rate more than doubling in 2016 compared to his career rate. Additionally, Siegrist enticed hitters to swing at a much higher percentage of balls outside the strike zone (O-Swing%). By slowing down his curveball, Siegrist fooled batters more often than he ever had.

If Siegrist can continue to develop and refine his curveball, it should become a weapon, especially against LHH. The pitch was already more than serviceable in its first season of implementation and will only progress as Siegrist improves his pitch sequencing and location mix.