FILE - In this Jan. 29, 2019, file photo, NFL Chief Medical Officer Dr. Allen Sills gestures while speaking during a health and safety tour at Mercedes-Benz Stadium for the NFL Super Bowl 53 football game in Atlanta. Days after the NFL revealed its hopes of conducting a normal regular season and playoffs, its chief medical officer warns that nothing is a certainty during the coronavirus pandemic. Sills, a neurosurgeon who has been with the NFL since 2017, says he and other league and team medical personnel have been in constant communication with health officials throughout the country, looking at the same data they are using to make public recommendations. (AP Photo/David J. Phillip, File)