Will Smith stars as Dr. Bennet Omalu, the forensic pathologist who first discovered football-related brain trauma in a professional player, in the trailer for the drama "Concussion."

Written and directed by Peter Landesman, the film chronicles the true story of Omalu's fight to bring public awareness to chronic traumatic encephalopathy, caused by repeated blows to the head, and the obstacles he faced in challenging the political, cultural and financial interests of the sports business.

Opening Dec. 25, "Concussion" also stars Alec Baldwin, Luke Wilson, Gugu Mbatha-Raw, Arliss Howard, Paul Reiser, David Morse and Albert Brooks.