Denver • No longer welcome on an NFL sideline, Colin Kaepernick turned to social media to make his point on the NFL’s opening Sunday.

In a tweet, Kaepernick gave a shout-out to "my brothers," Dolphins teammates Kenny Stills and Albert Watson, who were the only two players in the league to take a knee during the national anthem during Sunday's early games.

“They have not backed down, even when attacked and intimidated,” Kaepernick said in the tweet, which was accompanied by a picture of the Dolphins kneeling before their game. “Love is at the root of our resistance.”

It was Kaepernick, then with the 49ers, who sparked the anthem controversy by kneeling during the pregame ritual in 2016 — 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 contract on an NFL team and 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." One fan in Cleveland for the Steelers-Browns games was spotted in the stands wearing a Kaepernick jersey.

While Stills and Watson were kneeling during the anthem, teammate Robert Quinn raised his fist. Niners receiver Marquise Goodwin did the same at San Francisco's game at Minnesota. Jalen Ramsey and linebacker Telvin Smith Jr. of the Jaguars stayed in the locker room while the anthem was played.

Hours before Kaepernick's tweet, President Donald Trump took to twitter to dig at the NFL, linking low ratings for Thursday night's opener between Atlanta and Philadelphia (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!" he 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, and no players kneeled or protested in other ways.

That included Malcolm Jenkins, who raised his fist during the anthem last season but did not for the opener. During pregame warmups, he wore a shirt that read "Ca$h bail = poverty trap."

Jenkins 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,” he 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.”