Implications of Core and Hip Injuries on Major League Baseball Pitchers on the Disabled List.

PURPOSE: To investigate the frequency of core and hip injuries in Major League Baseball (MLB) pitchers and their impact on performance, workload, and pitch type.
METHODS: Demographic, performance data, and injury data were acquired for 330 MLB pitchers with 454 injuries placed on the disabled list (DL) from 2014 to 2015 seasons. Core and hip/groin injuries were analyzed in which injury year data were compared with career data and against other injury groups.
RESULTS: Core injuries represented 14% of all injuries and hip/groin injuries represented 7%. Average days on the DL for core injuries were 47.0 (standard deviation 5.6) days and 37.7 (standard deviation 8.1) days for hip/groin injuries. Return from the DL the same season for core injuries was 78% and 73% for hip/groin injuries. Core injuries returned to the DL 46% of the time (73% for noncore injuries) and hip/groin returned 56% of the time (60% for nonhip/groin injuries). No changes in workload were noted except starters with core injuries pitched less innings/game (5.3 vs 4.9 innings/game, P = .031) and more pitches/game (85.5 vs 78.4 pitches, P = .026). Fastball velocity decreased in the core injury group the year of injury (91.6 vs 92.2 mph, P = .001). Core injuries had slightly fewer home runs/9 innings and fewer strikeouts/9 innings; hip/groin injuries had slightly more strikeouts/9 innings, with all other performance statistics no different between the groups including earned run average and wins above replacement.
CONCLUSIONS: Core and hip injuries in MLB pitchers result in similar time on the DL compared with other injuries. Pitching workload during the year of injury does not seem to have a significant impact on sustaining a core or hip injury. Although there is a high rate of return to play from the DL, there is a high rate of reinjury in these pitchers more often for other injuries. LEVEL OF EVIDENCE: Level III, retrospective comparative study.