The football league said it made the decision to delay the games after seeking medical advice about the cases and consulting with the NFL Players Association.

The NFL said in a statement that the league is “seeing a new, highly transmissible form of the virus this week resulting in a substantial increase in cases across the league.”

“We continue to make decisions in consultation with medical experts to ensure the health and safety of the NFL community,” the statement noted.

Because of the postponement, a scheduled game between the Las Vegas Raiders and the Cleveland Browns will move from Saturday to Monday. Meanwhile, two games originally slated for Sunday—the Washington Football Team versus the Philadelphia Eagles, and the Seattle Seahawks versus the Los Angeles Rams—will now take place on Tuesday.

Just this week, over 100 NFL players have tested positive for COVID-19. As a result of the surge of the deadly virus, the NFL said on Thursday that it would update its COVID-19 protocols to include several new measures. 

“Effective immediately, all clubs will implement preventative measures that have proven effective: masking regardless of vaccination status, remote or outdoor meetings, eliminating in-person meals, and no outside visitors while on team travel,” the league said in a statement.

The National Hockey League also said on Friday that it would postpone some games because of COVID-19.