DOI: 10.1177/23259671261490739 ISSN: 2325-9671

Comparing Injury Rate and Injury Type in MLB Pitchers Before and After Pitch Clock Implementation: A 10-Year Analysis

Ty Langford, Kyle Stump, Sean Kelleher, Stephen Aronoff, Leslie Barnes
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Background:

The 2023 Major League Baseball (MLB) pitch clock reduced interpitch recovery time, raising concerns that reduced physiologic recovery could increase fatigue and injury risk in pitchers, particularly given the known links among fatigue, altered mechanics, and musculoskeletal injury.

Hypothesis:

We hypothesized that pitch clock implementation would be associated with increased pitcher injury rates, altered injured list (IL) utilization, and changes in injury type distribution.

Study Design:

Descriptive epidemiology study.

Methods:

Publicly available MLB data (The Baseball Cube, Fangraphs, Statcast; using years 2015-2025; excluding 2020) were analyzed. Injuries were defined as placement on the 10- or 60-day IL and categorized anatomically. Annual injury rate was the proportion of pitchers with ≥1 IL stint per season. A linear regression model using 2015-2022 data generated a counterfactual 2023 injury rate with 95% CI. DiD analysis compared pitchers (intervention group) to position players (control) pre- (2015-2022) and postimplementation (2023-2025). Injury distributions were compared using chi-square testing.

Results:

Pitcher injury rates increased preimplementation linearly by 4.3% per year ( R 2 = 0.75; P < .008), rising from 0.25 (2015) to 0.49 (2022). The observed 2023 rate (0.43) was below but within the predicted 0.54 (95% CI, 0.42-0.66). In DiD analysis, pitchers had an 11.7% lower preintervention injury rate than position players ( P = .017). Postimplementation, position player injuries decreased by 10% ( P = .0008), while pitchers experienced an 18% relative increase ( P = .005). Injury distribution differed significantly (χ 2 = 25.2; P = .0001), with elbow injuries increasing from 8.3% to 11.1% ( P < .01).

Conclusion:

Our study showed that, while overall pitcher injury rates did not exceed predicted trends in 2023, pitchers experienced a significant relative increase in injuries compared with position players, with a disproportionate rise in elbow injuries after the pitch clock's implementation. Thus, recovery time metrics can be seen as valuable data to inform pitcher injury prevention strategies.

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