The NFL is under pressure from falling television ratings, lawsuits over its handling of concussions, and fan opposition to player protests during the national anthem.

Yet investors keep lining up to help start new football leagues. On Tuesday, longtime NFL executive Bill Polian and TV and movie producer Charlie Ebersol became the latest entrepreneurs to join the fray when they unveiled plans for the Alliance of American Football.

Several short-lived football leagues have come and gone before, including the United Football League, United States Football League and XFL.

The league will aim for 21⁄2-hour games. To achieve that, there will be no kickoffs or extra-point kicks — only two-point plays — and a 30-second play clock, as opposed to the NFL’s 45-second clock. There will also be no TV timeouts, which will lead to about 60 percent fewer commercials.

The league will also draw from the pool of undrafted college players and others who are not on an NFL roster.

— The New York Times