Dallas Coach Jason Garrett opened a discussion of the pre-game demonstration by saying, “It’s been an interesting 48 hours for everybody.”

Mr. Garrett went on to describe a series of meetings between players, coaches and ownership before the game. “The objectives as much as anything else,” he said, “were to somehow, some way demonstrate unity and demonstrate equality and do so without involving, in any way, the national anthem.”

The demonstration at the beginning of ESPN’s broadcast of “Monday Night Football” showed that the league was continuing to express solidarity in the wake of comments by Mr. Trump, at a political rally in Alabama and in Twitter posts, about how any players that kneel or sit during the anthem should be fired. The situation escalated over the weekend, with Mr. Trump retweeting posts calling for a boycott of the N.F.L.

Most of the league’s owners have supported their players’ protests or demonstrations, either through statements to the news media or by standing with the players on the field during the playing of the anthem. Mr. Jones, however, was the first owner to kneel with his players.

Before the demonstration on Monday, no Cowboys players had participated in any sort of anthem protest, and Mr. Jones had indicated he preferred that remain the case.

“I do not think the place to express yourself in society is as we recognize the American flag,” he said last week in an interview with Fox Business. “So that’s not the place to do anything other than honor the flag and everybody that’s given up a little bit for it.”