Colin Kaepernick applauded the two Miami Dolphins players who took a knee Sunday during the national anthem ahead of their game against the Tennessee Titans.

The face of Nike's controversial new 'Just Do It' campaign tweeted out: '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!'

Dolphins wide receivers Kenny Stills and Albert Wilson became first players of the 2018 season to take a knee during Star-Spangled Banner as part of protests against police brutality and racial injustice in America.

The player protest issue returned to the spotlight after Nike selected former San Francisco 49ers quarterback Kaepernick - one of the key figures in the protests - to front a new advertising campaign.

Kaepernick and the NFL players protests have been heavily criticized by President Trump - who shared his thoughts on the matter Sunday.

Miami Dolphins wide receiver Kenny Stills (10) and Miami Dolphins wide receiver Albert Wilson (15) kneel during the national anthem before an NFL football game against the Tennessee Titans on Sunday

Stills and Wilson's protest came as it was revealed the NFL would not implement a national anthem policy this season

Former San Francisco 49ers quarterback Colin Kaepernick applauded the two Dolphins players who took a knee Sunday for their 'courage'

Kaepernick wrote in part: 'My Brothers @kstills and @ithinkisee12 continue to show their unwavering strength by fighting for the oppressed!'

Trump slammed the league for low ratings and blamed players for their protests during anthem as football season began in earnest.

'Wow, NFL first game ratings are way down over an already really bad last year comparison. Viewership declined 13%, the lowest in over a decade.

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

The NFL's opening showdown between the Philadelphia Eagles and Atlanta Falcons on Thursday evening earned only a 13.4 overnight Nielsen rating on NBC, the network announced Friday.

That is the smallest audience for an NFL regular season opener in the last 10 years, according to Sports Media Watch.

President Donald Trump blamed player protests although none knelt during the national anthem at Thursday's game

Trump wrote in part: 'Wow, NFL first game ratings are way down over an already really bad last year comparison. Viewership declined 13%, the lowest in over a decade'

But while Trump blamed protesters for the low viewership only one Eagles player, Michael Bennett, appeared to protest during Thursday's game.

Bennett stood for the start of The Star Spangled Banner but then sat on the team bench before the song had finished.

The defensive end, who has protested in the past, did not raise his fist as he has done at previous games. No Falcons player appeared to protest.

And no player was seen kneeling - an image the president latched on during the last football season was to hammer the league and question the players' patriotism.

The NFL is not expected to implement a new policy on the national anthem this season, league sources told ESPN on Sunday, hours before the day's games got started and the season began in earnest.

Robert Quinn of the Miami Dolphins raises his fist during the National Anthem on Sunday

Marquise Goodwin of the San Francisco 49ers raises a fist during the National Anthem before the game against the Minnesota Vikings at U.S. Bank Stadium on Sunday

Thus there will be no policy - and therefore no consequences - for players who take the knee during the anthem.

On Sunday, after Trump tweeted and reports revealed there would be no NFL policy on player protests this season, Stills and Wilson took a knee during the anthem.

Other players - such as Marquise Goodwin of the San Francisco 49ers and Robert Quinn of the Miami Dolphins - raised a fist in protest.

Trump has attacked the league in the ramp-up to opening season as standing for the national anthem is seen as an issue that could rally his base ahead of the November midterm election.

The New England Patriots stood before their game against the Houston Texans on Sunday

The Houston Texans players could also be seen standing during the national anthem

Meanwhile, also has called Nike's new campaign featuring the social rights activist Kaepernick 'inappropriate.'

At his Montana rally on Thursday night, the president again criticized the company's decision.

'I don't like what Nike did. I don't think it's appropriate what they did,' Trump said in a Fox News interview before the rally.

'I honor the flag. I honor our national anthem and most of the people in this country feel the same way.'

Trump also tweeted his criticism of the company.

No players knelt during the national anthem at Thursday's game

'What was Nike thinking?' Trump wrote on Twitter on Friday in a reference to the Kaepernick advert, which is honoring the 30th anniversary of the company's 'Just Do It' campaign.

The Kaepernick ad aired during the third quarter of Thursday's game.

In May, the NFL announced a compromise policy on the national anthem where players on the field had to stand while it played but athletes were given the option to remain in the locker room if they preferred.

But that policy was later shelved after protests from players.

Trump famously disinvited the Superbowl champions the Philadelphia Eagles to the White House after the victory when several players indicated they would not attend.