A recent Los Angeles Times article details the mad rush to file workers compensation claims in California by professional athletes following the passage of legislation barring claims by athletes from team outside California. Prior to the passage of AB 1309 professional athletes that played for teams outside of California could file a workers compensation claim in California if they had played just one game in California. Professional athletes have chosen to file their workers compensation claims in California in the past because California is one of the few states that allow claims for injury caused by cumulative trauma.

Cumulative injuries are those that occur over time and sometimes take years to reveal themselves.

For example injuries to knees and hips that cause the need for a total knee or hip replacement take many years to medically manifest the disability and the need for medical care. Similarly, high velocity bodily impacts like football blocks and tackles cause brain traumas such as dementia, and ultimately death, but not until tens of years after sports employment ends. All along, the team has known that the player will eventually require a total knee or hip replacement, a wheelchair, or even assisted living care. Yet, after AB1309 the team walks away free of liability transferring the cost of care to the player or, in most cases, taxpayer supported programs.

AB 1309 became effective on September 15, 2013. In the first two weeks of September, current and retired players filed 569 claims against NFL franchises, 283 claims against Major League Baseball clubs, 113 against National Hockey League teams and 79 against NBA squads. That is 1064 claims filed in two weeks, compared to 1,070 claims filed for the entire year of 2012.