Many athletes have been moved to comment on race and social justice more frequently in the past year after a series of police shootings of unarmed African-Americans and the support Mr. Trump has received from white supremacists.

Last year, Colin Kaepernick, then a quarterback for the San Francisco 49ers, began kneeling during the playing of the national anthem, to highlight, he has said, police brutality and racial injustice. He left the team this season and has not worked since, inspiring debate over whether teams are punishing him, while many players have knelt or made gestures in support of him during the anthem.

At the same time, some owners of N.F.L. teams have suggested that players should not take part in political demonstrations during games. None appeared to speak up for Mr. Trump on Saturday, while some of the owners who have donated primarily to left-leaning causes and politicians put out statements critical of him.

“It’s unfortunate that the president decided to use his immense platform to make divisive and offensive statements about our players and the N.F.L.,’’ said Mark Murphy, the president and chief executive of the Green Bay Packers.

Mr. Trump’s outbursts against athletes and their leagues came as he was smarting from yet another setback in his effort to repeal the Affordable Care Act, and as he worked to stoke enthusiasm among his core supporters in the deeply conservative state of Alabama, where he attended a campaign rally for Mr. Strange, whom many of them regard as an establishment Republican unworthy of their backing.