Already the most popular and valuable sports league in America, the NFL has made strides in recent years to become even more dominant. The league has expanded internationally, added holiday games, signed deals with new broadcast partners and attempted to make the sport ubiquitous.

With the 2024 season kicking off this weekend, no game more underscores the league’s recent business adventures than the Philadelphia Eagles vs. the Green Bay Packers in Sao Paulo, Brazil. It will be the NFL’s first game in South America. It will be broadcast on Peacock, NBC’s streaming service, rather than a broadcast network. And it will be the NFL’s first opening-week game on a Friday since 1970.

The NFL has had weekly games on Thursday and Monday nights for years, and a full schedule on Sunday afternoons and evenings. But the league has largely stayed away from Friday and Saturday games, thanks to an obscure law.

The Sports Broadcasting Act of 1961 provided the NFL and other leagues with an antitrust exemption for broadcasting. The law states that no professional football games can be played on Friday nights after 6:00 p.m. or on Saturdays from the second weekend in September through the second weekend in December. The law applies to all professional games that occur within 75 miles of a high school or college football game that occurs on the same weekend.

Peter O’Reilly, the NFL’s executive vice president of club business, international and league events, said the league typically likes to open the season with a Thursday night game the week of Labor Day, which is typically the second weekend in September. But with Labor Day falling on Sept. 2 this year, the league could schedule a Friday night game, since it was technically the first weekend of the month.

“The stars were aligned this year,” O’Reilly said.

Next year, the NFL could also hold a Friday game on opening weekend, since Labor Day falls on Sept. 1. O’Reilly said the league has not yet decided whether to hold another Friday game in September 2025.

Still, it wouldn’t be surprising to see a Friday game again a year from now, given how the league has found ways to infiltrate the calendar. The NFL is calling this year’s start “the biggest kickoff weekend ever,” starting with Thursday night’s game between the Kansas City Chiefs and Baltimore Ravens and ending with Monday night’s game between the New York Jets and San Francisco 49ers.

The NFL will have a Friday game again this year when the Las Vegas Raiders take on the Chiefs in Kansas City on Nov. 29, the day after Thanksgiving, which is commonly known as “Black Friday” and a popular shopping day. The league had its first “Black Friday” game last year, which, like this year, was broadcast on Amazon Prime and started at 3 p.m. ET, in a move likely to appease the Sports Broadcasting Act, which required Friday games to start no later than 6 p.m.

The NFL will have at least one Friday game on Christmas Day in 2026 as part of the league’s contract with Netflix. This year, Netflix will air two Christmas games. The streaming service will also have at least one game on Christmas Day in 2025 (a Thursday) and 2026 (a Friday).

The NFL will largely steer clear of Friday nights this fall. Still, as with the Eagles-Packers game in Brazil and its Black Friday and Christmas games, the league will try to expand its reach when possible and appropriate to generate revenue and give an NFL-obsessed fan base an extra day to watch the country’s most popular sport.