The new law requires professional athletes to have played at least two complete seasons for a team in California to be eligible to file for workers' compensation, the Los Angeles Times reported Tuesday.
Additionally, if an athlete has played seven or more seasons for a team outside California, they are ineligible for benefits even if they meet the two-season requirement within the state.
Brown signed the legislation Tuesday after more than a year of heavy lobbying by professional sports leagues, which stand to reduce their financial liabilities for concussions and other brain injuries sustained by players, the Times said.
Only five members of the Legislature voted against the law.
"Our workers' compensation system will no longer be unfairly targeted by out-of-state professional athletes," Democratic Assemblyman Henry T. Perea of Fresno said.
Critics of the law said it allowed wealthy owners and teams to shirk responsibility for employees injured on the job.
"It's a sellout to the billionaire owners" of professional teams, said Melissa Brown, a workers' compensation attorney in Sacramento. "Players are suffering these terrible injuries, especially the older ones. They are going to be without a remedy."