First they disagreed over the merits of the settlement. Now they're fighting over who should be paid for it.

A group of prominent plaintiff's lawyers are battling for their cut of potentially $21 million in legal fees related to a pending concussion settlement with the National Collegiate Athletic Association, one of many litigation battles that the governing body for collegiate sports now faces.

The dispute between Chicago-based Jay Edelson and Steve Berman, a co-founder of Seattle-based plaintiffs powerhouse Hagens Berman Sobol Shapiro, began as a strategy disagreement as late as 2014.