The Impact of the Pitch Clock on UCL Surgery Rates and Performance in Major League Baseball Pitchers

Major League Baseball (MLB) implemented a new Pitch Clock in 2023, sparking debate on whether it has affected injuries among pitchers.

Introduction of the Pitch Clock would have no impact on ulnar collateral ligament (UCL) surgery rates or pitcher performance.

Cohort study; Level of evidence, 3.

Season-to-season surgery trends were evaluated, and a retrospective case-control analysis was conducted on all MLB pitchers who underwent UCL surgery from the beginning of the 2018 season to the end of the 2024 season. Matched controls were identified in a 2 to 1 ratio, similar to previous studies, and pitch timer data from matched pairs since 2023 were compared. Advanced analytic and pitch-tracking metrics were also analyzed to see whether there was any impact from the pitch timer. Data were collected from publicly available web sources affiliated with MLB and have been used in previous studies. Statistical analysis consisted of unpaired t tests comparing cases and controls, as well as binary logistic regression.

There was no difference in the number of UCL surgeries per season since the Pitch Clock was implemented in 2023 compared with the 4 full seasons prior (P = .64). There was a significant trend of surgeries earlier in the season since Pitch Clock implementation (P = .04). Furthermore, 52 MLB pitchers who underwent a UCL surgery were then identified alongside 104 matched controls. No significant differences were observed in pitch timer duration or fast pitch percentage between cases and controls. Also, no significant differences were found in velocity, spin rates, pitch quality (Stuff+), overall pitching ability (Pitching+), strike-zone command (Location+), release points, approach/release angles, or extension. Outside of vertical movement, binary logistic regression did not identify any potential risk factors for UCL injury. No significant differences were found in pitch-tracking metrics between cases or matched controls before (2018-2022) and after implementation of the Pitch Clock (2023-2024) (P > .05).

Overall, this preliminary study suggests that the newly implemented Pitch Clock may not increase the overall rate of UCL surgeries in MLB pitchers. However, there has been a significant increase in the percentage of starting versus relief pitchers undergoing UCL surgery since the inception of the Pitch Clock. Reassuringly, the Pitch Clock also did not have a concerning impact on pitching performance in MLB pitchers. Further monitoring of injury trends after the implementation of the Pitch Clock in MLB is warranted.