On Thursday, former New England Patriots tight end Aaron Hernandez, who committed suicide in April while serving a life sentence for murder, was posthumously diagnosed with a "severe" case of chronic traumatic encephalopathy, a degenerative brain disease linked to head trauma. The New York Times reported that diagnosis, as well as the fact that Hernandez's lawyer, Jose Baez, plans to sue the NFL and the Patriots for $20 million on behalf of Hernandez's 4-year-old daughter. 

"Aaron Hernandez succumbed to the symptoms of CTE," the suit states, in part. "As a result of the defendants' conduct and the injury experienced by Aaron, Avielle Hernandez was deprived of the love, affect, society and companionship of her father while he was alive."

The NFL responded to news of the suit Friday, telling reporters on a conference call, "We intend to contest the claims vigorously," according to USA Today. The report noted that the suit could face a potential issue that could derail the claim that the Patriots and/or the NFL should be held financially responsible: 

The lawsuit could face one major league hurdle: Hernandez was not listed among the players who opted out of a concussion settlement with the league.

Players whose careers concluded before July 2014 "gave up the right to sue the NFL Parties" unless they opted out, according to the settlement. Hernandez's last NFL game was in January 2013 before he was arrested -- and ultimately convicted -- for the murder of former semi-pro football player Odin Lloyd.

"By not opting out, his daughter is now bound by the terms of the settlement," David S. Weinstein, a former assistant U.S. attorney and current partner at the firm Hinshaw & Culbertson, told USA TODAY Sports. "The NFL and Patriots have an easy road to dismissal."

Hernandez was 27 years old at the time of his death, and Baez stated that his case of CTE was "the most severe case [researchers] had ever seen in someone of Aaron's age." CTE has been shown to have extreme side effects, as several former NFL players experienced symptoms of depression and some of them, like Hernandez, committed suicide. Because CTE cannot be diagnosed until after death, it was not known until Thursday whether or not Hernandez had CTE.