The Denver Broncos have no quarterbacks. The San Francisco 49ers have no home stadium or practice facility. And the Baltimore Ravens may not have enough players available for their next game, which has already been pushed back twice.

The COVID-19 pandemic caused major disruptions around the NFL on Saturday, again calling into question the league’s plan to play a full schedule after several weeks that went relatively smoothly. Multiple people familiar with the NFL’s investigation told The Associated Press that all four of the quarterbacks on Denver’s roster were ineligible to play Sunday against the New Orleans Saints.

The Ravens, meanwhile, put six more players on the COVID-19 list, which is for players who’ve either tested positive for the virus or had close contact with an infected person. Baltimore had already disciplined an unidentified staff member for violating COVID-19 protocols, and the outbreak – the worst on any team this season – left the Ravens with three defensive linemen and one quarterback available. The Tennessee Titans previously had their Week 4 game against the Pittsburgh Steelers postponed because of a COVID-19 outbreak,  giving both teams an unexpected bye week, and their subsequent game against Buffalo was pushed back to a Tuesday. The Ravens’ game at rival Pittsburgh was initially scheduled for Thanksgiving night and was moved to Sunday before being postponed again for Tuesday. Some Steelers players complained about their schedule being disrupted again because of another team’s failure to contain an outbreak. But the Steelers placed starting running back James Conner on the COVID-19 list Saturday, joining three other teammates. NFL Commissioner Roger Goodell has warned all 32 teams that forcing changes to the schedule could lead to them being stripped of draft choices or even forfeiting games.

The league has thus far avoided any forfeits and was on track to complete its regular season on time.