ERIE, Pa. - Erie native and former National Football League defensive back Cliff Crosby supports players who used the national anthem to protest President Donald Trump Sunday.

"We all have the freedom of speech," Crosby said, noting he not only supports those saluting the flag, but also those who wish to sit or kneel in protest. "But the problem with the freedom of speech is that is comes with consequences."

The controversy, stemming from Trump's remark at a campaign event Friday in Alabama for a Republican U.S. Senate candidate, Luther Strange.

"Wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, say 'get that son of a b**** off the field right now'?" Trump said.

Crosby played 6 N.F.L. seasons between 1999-2004, spending most of his time with the St. Louis Rams and the Indianapolis Colts. But the league didn't encourage players to participate in the anthem until 2009.

"So you never really had to think about it," Crosby recalled. "It was just something that you did."

Three N.F.L. teams, including the Pittsburgh Steelers, remained in the locker room during the anthem Sunday. Left tackle and former U.S. Army Ranger Alejandro Villanueva was the only teammate visible, unexpectedly emerging feet away from his team on the edge of the tunnel near the field. The Steelers had agreed to remain in the locker room prior to kickoff.

"Some have opinions, some don't," Tomlin said. "We wanted to protect those that don't, we wanted to protect those that do. We came here to play a football game today."

Local Steelers fans in Chicago for the game say that amplified the situation.

"Everything around Soldier Field is dedicated to the military and the history of the military," said Pat Hargest, of Edinboro regarding the Chicago Bears' stadium, Soldier Field. "It was remarkably louder, there were more 'boos' than I'm used to hearing."

Despite the controversy around the league, Villanueva's move was popular among some Steelers fans. His No. 78 jersey, the top-selling in the NFL Shop online store on Monday.

During a news conference late Monday, Villanueva said he didn't tell head coach Mike Tomlin of his last-minute decision before Sunday's game -- only team captains Ben Roethlisberger and Cam Heyward.

"Unintentionally, I left my teammates behind," said Villanueva, who later said he felt embarrassed by the picture that shows him standing alone. "Everybody sees an image of me standing by myself, everybody thinks that the team and the Steelers are not behind me and that's absolutely wrong."