Receivers Stills and Albert Wilson kneeled behind teammates lined up standing along the sideline.
Robert Quinn, a defensive end for the Dolphins, raised his fist.
There were no apparent demonstrations by the Buccaneers.More news: Missing billions: Ex-Malaysian PM Najib Razak denies money laundering in court
In July, the NFL made a decision to suspend its new anthem policy which required all players on the field to stand for the national anthem.
"As a black man in this world, I've got an obligation to raise awareness", Quinn said. That rule has since been pulled off the table with the hope that the players and owners can come to a negotiated agreement before the season begins.
"The NFL and NFLPA, through recent discussions, have been working on a resolution to the anthem issue", read the joint statement.More news: New York Yankees: Is the American League East race over?
Stills has routinely knelt for the anthem during his time with the team. Seattle coach Pete Carroll said the team discussed the topic and chose to support individual decisions. This is not going to become a distraction, and Jacksonville's not going to become a distraction for this team.
"While those discussions continue, the National Football League has agreed to delay implementing or enforcing any club work rules that could result in players being disciplined for their conduct during the performance of the anthem". In July, the league and players association jointly announced that the new rule was "frozen" until further notice.
It was a show of solidarity with the ongoing protests against police brutality and racial injustice, launched by former NFL quarterback Colin Kaepernick in 2016 and banned by NFL Commissioner Roger Goodell in May.
The NFL modified its national anthem protocol in May, prohibiting any sort of demonstrations for the 2018 season, but allowing players to remain in the locker room during the anthem if they chose to.More news: Argentine Senate rejects historic abortion law