Graphic displays of MLB pitching mechanics and its evolutions in PITCHf/x data

Abstract: Systemic and idiosyncratic patterns in pitching mechanics of 24 top starting pitchers in Major League Baseball (MLB) are extracted and discovered from PITCHf/x database. These evolving patterns across different pitchers or seasons are represented through three exclusively developed graphic displays. Understanding on such patterned evolutions will be beneficial for pitchers' wellbeing in signaling potential injury, and will be critical for expert knowledge in comparing pitchers. Based on data-driven computing, a universal composition of patterns is identified on all pitchers' mutual conditional entropy matrices. The first graphic display reveals that this universality accommodates physical laws as well as systemic characteristics of pitching mechanics. Such visible characters point to large scale factors for differentiating between distinct clusters of pitchers, and simultaneously lead to detailed factors for comparing individual pitchers. The second graphic display shows choices of features that are able to express a pitcher's season-by-season pitching contents via a series of 3(+2)D point-cloud geometries. The third graphic display exhibits exquisitely a pitcher's idiosyncratic pattern-information of pitching across seasons by demonstrating all his pitch-subtype evolutions. These heatmap-based graphic displays are platforms for visualizing and understanding pitching mechanics.