Background: Shoulder instability is a significant cause of disability in pitchers. The advent of advanced pitch-tracking technology now provides an opportunity to investigate the mechanical factors associated with these injuries on a large scale in Major League Baseball (MLB).
Purpose/hypothesis: The purpose of this study was to identify preinjury advanced analytic and pitch-tracking metrics associated with surgically treated shoulder instability in MLB. It was hypothesized that pitchers requiring surgery would demonstrate distinct preinjury profiles in advanced performance analytics and Statcast data compared with matched controls.
Study design: Case-control study; Level of evidence, 3.
Methods: MLB pitchers who underwent primary capsulolabral repair from 2017 to 2024 (n = 35) were identified using public web sources used in previous studies. Each case was matched 2:1 with uninjured control pitchers (n = 70) based on age, role, handedness, season, and total pitch count. Advanced analytic and various pitch-tracking metrics were compiled from MLB-sponsored databases commonly used in player evaluation and prior research. The statistical analysis included unpaired t tests to compare groups and binary logistic regression to identify risk factors.
Results: MLB pitchers who underwent capsulolabral surgery demonstrated superior preinjury performance metrics (including the FanGraphs version of wins above replacement [fWAR], fielding independent pitching [xFIP], expected earned run average [xERA], Stuff+, and walks plus hits per inning pitched) and pitch characteristics (including fastball velocity and spin rate), along with a more medial release point compared with controls. Binary logistic regression identified both Stuff+ and a medial release point as independent factors associated with surgery. Notably, the composite Stuff+ metric demonstrated a stronger association than velocity or spin rate alone in the final model (P < 05 for all significant factors).
Conclusion: Several modern advanced analytic and pitch-tracking metrics were looked at as potential risk factors for shoulder instability in MLB pitchers for the first time. Pitchers who underwent capsulolabral surgery were more likely to throw harder with higher spin rates and a more medialized release point than matched controls. Overall, MLB pitchers who were more effective and had superior Stuff+ were at the highest risk for shoulder instability requiring surgical intervention. These findings point to a potential trade-off in modern pitching; the pursuit of elite performance is linked to a greater likelihood of injury.
Keywords: Statcast; baseball; biomechanics; labrum; pitching mechanics; shoulder.
© The Author(s) 2026.