DENVER -- Colin Kaepernick called them his brothers.

Miami Dolphins teammates Kenny Stills and Albert Wilson were the only two players to kneel during the national anthem on the NFL's season-opening Sunday, and Kaepernick, who is no longer welcome on an NFL sideline, made sure to offer his thanks to them via social media.

My Brothers @kstills and @ithinkisee12 continue to show their unwavering strength by fighting for the oppressed! They have not backed down, even when attacked and intimidated. Their courage will move the world forward!



"Love is at the root of our resistance!"✊🏾 pic.twitter.com/2kSsX4s7EU — Colin Kaepernick (@Kaepernick7) September 9, 2018

It was Kaepernick, then with the San Francisco 49ers, who sparked the anthem controversy in 2016 by kneeling during the pregame ritual -- his way of protesting policy brutality and social injustice in America.

Since opting out of his contract after that season, Kaepernick has been unable to land a job with an NFL team, and he is suing the league for collusion.

But his voice is still being heard. Last week, Nike introduced an ad featuring the quarterback and his message: "Believe in something, even if it means sacrificing everything."

On Sunday, Kaepernick's message got through to his friends in Miami.

"I know he has our back," Stills said. "Really, there has been a huge difference between when we first started protesting and now. A lot of people are reaching out and supporting us, so I really appreciate that. To everybody out there ... let's keep doing our best to make positive change and have these conversations and make our country a better place."

While Stills and Wilson were kneeling during the anthem, teammate Robert Quinn raised his fist. Niners receiver Marquise Goodwin did the same before San Francisco's game at the Minnesota Vikings. In Los Angeles, Chargers left tackle Russell Okung raised his fist. Broncos receiver Demaryius Thomas and linebacker Brandon Marshall, as well as Seattle Seahawks linemen Duane Brown and Quinton Jefferson, retreated to their respective tunnels in Denver while the anthem played.

At the peak of the anthem protests in 2016, as many as 200 players would partake. During most weeks last season, the Seahawks led the way with the most players doing something to make a statement; though their participants had fallen to two to start the 2018 campaign, Brown wasn't worried.

"I made my decision. That was my decision," he said. "I wasn't paying attention to see what other teams or other players are doing."

The NFL briefly had a policy in place in May regarding the anthem but rescinded it after the players' union filed a grievance, which sent the league to the negotiating table with the union. Those talks are ongoing. Brown said he hasn't heard any word from the union dissuading player protests during the anthem.

"I don't think that would be the best idea to try to get people to move on from it," he said. "The country hasn't moved on from it, so I'm not going to move on from it, either."

Among those keeping the issue front and center is President Donald Trump, who sent a tweet of his own several hours before Kaepernick's, taking digs at the NFL and linking low ratings for Thursday night's opener between the Atlanta Falcons and Philadelphia Eagles (lowest for an opener since 2008) to players who refuse to stand for the anthem.

"If the players stood proudly for our Flag and Anthem, and it is all shown on broadcast, maybe ratings could come back? Otherwise worse!" Trump tweeted.

CBS and Fox, which carried Sunday afternoon's games, have said they did not plan on televising the anthem.

However, NBC did show the anthem on Thursday night (but not before Sunday night's Chicago Bears-Green Bay Packers game) and no players kneeled or protested in other ways.

That included Malcolm Jenkins of the Eagles, who raised his fist during the anthem last season but did not for the opener. During pregame warm-ups on Thursday, Jenkins wore a shirt that read, "Ca$h Bail = Poverty Trap."

Jenkins, a founder of the Players Coalition that was formed to tackle issues similar to those Kaepernick is concerned about, said he would like to move the focus away from the anthem.

"I think there's a huge need for us to turn the attention to not only the issues, but what players are actually doing in their communities to promote change," Jenkins said. "We're trying to move past the rhetoric of what's right or what's wrong in terms of the anthem and really focus on the systematic issues that are plaguing our communities."