WASHINGTON — President Trump turned professional sports into a political battleground, directing full-throated ire toward African-American athletes who have spoken out against him and prompting a response from the National Football League, its players, and one of basketball’s top stars.
On Friday night and Saturday morning, Trump ensnared and agitated the most powerful sports league in North America and perhaps the most popular athlete in American team sports.
At a political rally in Alabama on Friday, Trump called on NFL owners to release players who demonstrated during the national anthem in the manner of former San Francisco 49ers quarterback Colin Kaepernick, who knelt to draw attention to police violence against African-Americans.
Saturday morning on Twitter, Trump rescinded a White House invitation to Stephen Curry of the NBA champion Golden State Warriors, although it is unclear whether the Warriors had been invited in the first place.
‘‘Going to the White House is considered a great honor for a championship team. Stephen Curry is hesitating,therefore invitation is withdrawn!’’ Trump tweeted.
The tweet followed comments he made Friday night in at a Huntsville, Ala., rally for Republican senator Luther Strange, who is running in a special GOP primary election to remain in the seat vacated by Attorney General Jeff Sessions.
The president also suggested that fans consider walking out in protest ‘‘when somebody disrespects our flag.’’
‘‘That’s a total disrespect of our heritage. That’s a total disrespect of everything that we stand for,’’ Trump said, encouraging owners to act.
‘‘Wouldn’t you love to see one of these NFL owners, when somebody disrespects our flag, you’d say, ‘Get that son of a bitch off the field right now. Out! He’s fired,’’ Trump said to loud applause.
On the issue of violence on the field, Trump said players are being thrown out for aggressive tackles, and it’s ‘‘not the same game.’’
Over the past few seasons, the NFL and college football have increased penalties and enforcement for illegal hits to the head and for hitting defenseless players. The rules are designed to limit brain trauma.
A July report on 202 former football players found evidence of a debilitating brain disease linked to repeated head blows in nearly all of them. The league has agreed to pay $1 billion to retired players who claimed it misled them about the concussion dangers of playing football.
Trump took up the subject of national anthem protests after bemoaning the rules penalizing dangerous hits.
‘‘The NFL ratings are down massively,’’ Trump said. ‘‘Now the No. 1 reason happens to be they like watching what’s happening with yours truly. They like what’s happening. Because you know today if you hit too hard — 15 yards! Throw him out of the game! . . . They’re ruining the game! That’s what they want to do. They want to hit.’’
‘‘But do you know what’s hurting the game more than that?’’ Trump added. ‘‘When people like yourselves turn on television and you see those people taking the knee when they’re playing our great national anthem.”
“The only thing you could do better is if you see it, even if it’s one player, leave the stadium. I guarantee things will stop,’’ he said. “Things will stop. Just pick up and leave. Pick up and leave. Not the same game anymore, anyway.’’
Kaepernick, despite a clear case his performance and ability warranted at least a chance at a roster spot, remains unsigned. NFL owners collectively donated more than $7 million to Trump’s presidential campaign, and New England Patriots owner Robert Kraft gave Trump a Super Bowl ring this summer.
NFL Commissioner Roger Goodell, who has waffled in varied comments regarding Kaepernick’s protest, responded to Trump on Saturday.
‘‘Divisive comments like these demonstrate an unfortunate lack of respect for the NFL, our great game and all of our players, and a failure to understand the overwhelming force for good our clubs and players represent in our communities,’’ Goodell said in a statement.
NFLPA Executive Director DeMaurice Smith said, ‘‘The union . . . will never back down when it comes to protecting the constitutional rights of our players as citizens, as well as their safety as men who compete in a game that exposes them to great risks.’’
Curry attracted the president’s attention Friday afternoon. The Warriors announced they vote as a team whether to attend the White House, as is tradition for champions from all sports. Curry said he would vote against going.
‘‘We don’t stand for basically what our president . . . the things that he said and the things that he hasn’t said in the right terms that we won’t stand for it,’’ Curry said. ‘‘And by acting and not going, hopefully that will inspire some change when it comes to what we tolerate in this country and what is accepted and what we turn a blind eye to.
‘‘It’s not just the act of not going,’’ he said. “There are things you have to do on the back end to actually push that message into motion.
“You can talk about all the different personalities that have said things and done things, from Kaepernick to what happened to [Michael] Bennett to all sorts of examples of what has gone on in our country that we need to kind of change,’’ Curry said. “And we all are trying to do what we can, using our platforms, using our opportunities to shed light on that.’’
LeBron James of the Cleveland Cavaliers slammed Trump on Twitter. “Going to White House was a great honor until you showed up!’’ he wrote Saturday.