Return to Performance After Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers: A Case-Control Assessment of Advanced Analytics, Velocity, Spin Rates, and Pitch Movement.

Background: There are limited data on the performance or pitching metrics of Major League Baseball (MLB) pitchers who returned to play after ulnar collateral ligament reconstruction (UCLR).

Purpose: To describe MLB pitcher performance after return from primary UCLR, compare the velocity and pitch characteristics against the preoperative season, and determine if performance analytics can predict successful return to pitching after UCLR.

Study Design: Case-control study; Level of evidence, 3.

Methods: This study included 63 pitchers who underwent primary UCLR between 2015 and 2019. Publicly available advanced analytics and pitch metrics from the first 2 postoperative seasons were compared with the preoperative (index) season as well as with an uninjured control group.

Results: Overall, 57% of the pitchers successfully returned to the MLB level. Although they threw significantly fewer pitches ( = .012) and innings ( = .022) in postoperative year 1 as compared with the index season, there were no significant differences in pitch velocity, release extension, perceived velocity, or performance as measured by advanced analytics. Also, as compared with the index season, returners demonstrated increased postoperative spin rates on curveballs ( = .001) and sliders ( = .010), and curveball horizontal movement was significantly increased ( = .007); however, horizontal movement was significantly decreased for 4-seam fastballs ( = .026), changeups ( = .005), and sinkers ( = .019). The vertical movement on 4-seam fastballs was greater ( < .001) in postoperative year 1, and the vertical movement on curveballs ( = .031) and sinkers ( = .010) was greater in postoperative year 2 when compared with the index season. Pitchers who failed to return to the MLB level had a lower preoperative strikeout percentage ( = .047), fewer strikeouts per 9 innings pitched ( = .046), fewer wins above replacement ([WAR]; = .026), and lower player value ( = .030) than the pitchers who returned.

Conclusion: Pitchers returning to the MLB level after UCLR demonstrated changes in pitch movement profiles and spin rates postoperatively, but there were no differences in velocity or many advanced analytics upon return. Pitchers with lower strikeout metrics, fewer WAR, and less player value before surgery may have an elevated risk of failing to return to the MLB level.