The judge overseeing the National Football League’s $1 billion concussion settlement has appointed an expert to look into the reasonableness of attorney fees in the case.

U.S. District Judge Anita Brody of the Eastern District of Pennsylvania on Thursday appointed Harvard Law School professor William Rubenstein to provide an expert opinion on whether the court should cap the percentage of recovery any class member would be required to pay his attorney. Brody’s order also asked Rubenstein to consider how high or low the cap should be, weigh the reasonableness of requiring class members to pay 5 percent of their recoveries to the common benefit fund, and how to avoid any question of “double-dipping.”