The N.F.L. has never been more prosperous or more popular, reportedly generating more than $23 billion in revenue last year. The league just kicked off its 106th season. But it still faces a crisis over concussions and other head injuries, one it has been slow to resolve. Tackle football’s gladiatorial style may seem perfectly suited to a world in which the leader of the Ultimate Fighting Championship, Dana White, has President Trump’s ear. Yet lingering concerns about the inherent risks of the sport have created a demand for a safer alternative, both for new players and potential fans.

Flag football, that playground pastime, has found its moment. It offers a means of enjoying the beauty of the sport, to girls as well as boys, with a significantly lower risk of wrecking your brain or the horror of watching that happen to others. Even the N.F.L. is pushing it hard — not as a replacement for its more violent main product but as a more palatable addition.

The N.F.L.’s Pro Bowl is now a flag game, in large part to avoid injuries. Flag football will make its Olympic debut in 2028 in Los Angeles for men and women. Seventeen states — including California, New York and Florida — have added flag football as a high school varsity sport for girls. And if the N.F.L. has its way, that number will soon be 50, thanks to an initiative, Flag 50, that the league promoted in a flashy Super Bowl commercial.

More boys are playing, too. The N.F.L.’s executive vice president for football operations, Troy Vincent, has called flag “the future of the game of football.”

Vanita Krouch, the quarterback of U.S.A. Football’s women’s flag football national team, credits the pop star Taylor Swift in part for girls’ interest in the gridiron. Because of her appearances at N.F.L. games to cheer on her fiancé, Travis Kelce, “these little girls are suddenly watching Sunday football with their dads,” Krouch said.