The player protests have become a divisive topic of debate, and the National Football League and players union still haven't said whether players will be punished this season if they choose to kneel or demonstrate during the anthem.
Under the old policy, players had to be at the field for the anthem, but while they were "strongly encouraged" to stand, they were not required to do so.
"Wow, NFL first game ratings are way down over an already really bad a year ago comparison", the president tweeted, asking if ratings would improve "if the players stood proudly for our Flag and Anthem".
"Viewership declined 13 per cent, the lowest in over a decade".
Players have steadfastly maintained their protest is aimed at social and racial issues while Trump has pushed that players should be fired for disrespecting the flag.
In New York, Jacksonville Jaguars cornerback Jalen Ramsey and linebacker Telvin Smith Jr., who had stayed in the locker room during the anthem for the pre-season, opted to stand quietly on the sidelines for their opening game.
The NFL's national anthem policy is anything but certain, and the league is not expected to implement a new one this season. If the players stood proudly for our Flag and Anthem, and it is all shown on broadcast, maybe ratings could come back? Colin Kaepernick, the former San Francisco 49ers quarterback and current Nike spokesman, praised Stills and Wilson in a tweet on Sunday.
Nike reported a 31% sales boost during the Labour Day holiday weekend this year over last year after the advertisement debuted online.