July 22, 2021 | NFL
In a memo released to NFL clubs, the NFL announced they will not extend the season. If a game that was delayed because of a COVID-19 outbreak cannot be re-scheduled during the regular 18-week schedule, the team with the outbreak will forfeit the game and be financial responsible for any loses. Players of both teams also will not be paid.
Original source: https://www.nfl.com/news/nfl-covid-19-outbreaks-unvaccinated-players-forfeit-cancelled-game