The official football for the National Football League, with the signature of new commissioner Roger Goodell, sits within the NFL logo painted on the field prior to a game on November 26, 2006 between the Carolina Panthers and the Washington Redskins "This upward trend, coupled with the onset of colder weather driving individuals indoors, has resulted in an increased risk of infection among players and staff," the league said in a memo sent to teams Tuesday and obtained by The Associated Press. "Our experts and data confirm that getting vaccinated remains our strongest defense against contracting and transmission of the virus within club facilities."Additional masking will not be required outdoors or in the practice bubble.