Impact of the 7-Day Disabled List Rule Change on Economics and Performance After Reported Concussion Injuries in Major League Baseball.

Background: The incidence of concussions is increasing in Major League Baseball (MLB), and the cost of these injuries in 2008 was reportedly as high as US$423 million. Team officials are more aware of concussion injuries, and one measure to address this issue was the creation of a concussion-specific 7-day disabled list (DL) in 2011.

Purpose: To evaluate concussion trends among MLB players and the impact of concussion-specific 7-day DL status on postinjury player performance and team financials.

Study Design: Descriptive epidemiology study.

Methods: From 2005 to 2016, a total of 112 players placed on the DL because of a concussion were identified using the MLB website and were verified using established news databases. Salary information for players was collected using MLB published data, and cost was calculated with a previously published formula utilizing the injured player's salary per game and adding the cost of his replacement. Performance metrics were compared before and after the rule change.

Results: The mean number of days on the DL decreased from 38.8 before 2011 to 29.2 after 2011. The mean annual cost per player before 2011 was $1.1 million and decreased to $565,000 after the rule change. Regression analyses demonstrated a downward trend in the mean cost ( -0.61, < .001). A comparison of postinjury performance metrics showed no significant differences with decreased time on the DL.

Conclusion: The minimum 7-day DL change has not had a negative impact on reporting; instead, it has demonstrated decreased time on the DL and lower associated team costs. Performance metrics demonstrated no differences compared with before the rule change, suggesting that players are not negatively affected by decreased time on the DL.