NFL club owners are considering potential 15-yard penalties for kneeling during the national anthem among ways of coping with a backlash over player protests, Sports Illustrated reported Tuesday.

According to a story on the magazine's website, owners set aside three hours to talk about the anthem issue, which US President Donald Trump elevated into a major controversy last year.

Ideas to handle players kneeling during the anthem included allowing home teams to decide if players should be out of the locker room during the pre-game playing of "The Star-Spangled Banner" or not.

If players are on the sideline, then 15-yard penalties could be imposed on teams with players who kneel during the anthem.

The kneel protest was started by former San Francisco 49ers quarterback Colin Kaepernick in 2016 as a way to protest police brutality, racial injustice and social inequality.

In 2017, he was unable to get an NFL job and the kneel protest was waning until Trump made an issue of it, saying the move was disrespectful to the nation and the flag -- motivations never assigned by Kaepernick.

Free agents Kaepernick and Eric Reid are suing the NFL, saying league owners colluded to keep them unsigned.