When the National Basketball Association season starts, players need to stand for the national anthem, according to league Commissioner Adam Silver.

In a move to stay ahead of the rising tide of fan and corporate anger against athletes who are kneeling or sitting during the national anthem, Silver said that standing for the anthem is a league rule.

NFL fans have reacted with boos and vows to quit watching the game because of rampant kneeling during the anthem, and some football corporate sponsors are already worried about continued declining ratings. Aware of those problems, Silver opted to be pro-active on any potential controversy surrounding his league.

“Many of our players have spoken out already about their plan to stand for the anthem,” Silver said Thursday. “And I think they understand how divisive an issue it is in our society right now.”

Silver said playing the anthem is a time for respect and reflection, even though a quarter of the NBA’s players are not American. He noted that many teams locked arms last season, and he wants that practice to continue while standing.

“It’s been a rule as long as I’ve been involved with the league, and my expectation is that our players will continue to stand for the anthem,” Silver said.

However, Silver did not indicate what would happen for violations of his instructions. “If that were to happen, we’ll deal with it when it happens.”

Silver’s statements come less than a week after President Donald Trump declared that last season’s NBA champion Golden State Warriors would not be invited to the White House, as tradition dictates. All-star guard Stephen Curry indicated he didn’t want to come, and other players indicated reluctance, leading to Trump’s reaction.

Silver thinks NBA players have other opportunities, either by continuing their community service efforts or through the media, to make their voices heard. “I’m hoping once again that this league can play a constructive role there,” Silver said.