Prior to Mike Webster's death, during the worst of his CTE-related mental health difficulties, this movie shows him alone in his truck (where he has started living) when he removes his pants and applies a Taser-style electronic weapon to his own heavily scarred leg. Although the movie never provides an explanation for this action, articles on ESPN.com and in GQ covering Webster's death and Bennet Omalu's research explained that Webster did this to himself because at that point in his illness, he was unable to fall asleep, but the Taser would at least render him unconscious for periods of time.
During the theatrical release of the movie, Sony Pictures offered free advanced screenings and free screenings at Cinemark theaters to former NFL players and their families.
To prepare for the movie, Will Smith and writer and director Peter Landesman observed autopsies, including two done by Dr. Bennet Omalu.
Former NFL Patriot tight end Aaron Hernández was diagnosed posthumously with CTE following his troublesome death in April 2017, in a late stage never before seen in a 27-year old
In his office, when Dr. Julian Bailes (Alec Baldwin) prepares Mike Webster (David Morse) for a Haldol injection by helping him on the sofa, there's a close-up of a mounted cross-section of a bird's skull placed on the table to Mike's right. The skull is a woodpecker's and shows the unique tongue system that functions as a shock absorber for its brain when it pecks at trees. Dr. Omalu explains the mechanism to Dr. Steve DeKosky later in the film. ("It is the anatomical equivalent of a safety belt for its brain.")