The NFL has approved a plan in which teams can wear alternate helmets with their throwback uniforms starting in 2022, the league has announced.

Teams must tell the NFL of their plans for an alternate-color helmet for the 2022 season by July 31, even though they won't be used for another year.

The use of a second helmet was dropped in 2013 over concerns that wearing more than one helmet might not be safe for players. As those concerns have eased, clubs have lobbied for a second helmet because options for alternate jerseys were expanded in 2018.

The second helmet can be worn only with so-called classic, alternate or Color Rush jerseys, and all players must be fitted for both helmets before training camp.