Silver reportedly cited a league rule, which requires players to stand during "The Star-Spangled Banner."
When asked how the NBA would handle a player kneeling or sitting, Silver said the league office would "deal with it when it happens," per USA Today's Jeff Zillgitt.
NBA TV relayed video of Silver's complete comments:
This is not a new stance from Silver.
In October 2016, the commissioner told B/R Mag's Howard Beck and Jonathan Abrams he wanted players to abide by league policy.
"I'd only say that we have a rule that requires players to stand respectfully for the anthem," Silver said. "That is our rule. I'm not going to prejudge any player conduct. We'll deal with any situations that present themselves. But I’ve been very clear that our expectation is that our players will stand for the anthem."
ESPN.com's Bobby Marks relayed a screenshot of the policy straight from the league rulebook:
Silver also addressed President Donald Trump's decision not to invite the Golden State Warriors to the White House in celebration of their 2016-17 championship.
"It's disheartening to see so much disunity in society," he said, according to The Vertical's Michael Lee.
That remark echoed the sentiment Silver espoused in a formal statement after Trump tweeted the Warriors would not be welcomed to 1600 Pennsylvania Avenue.
"I was in favor of the team visiting the White House and thought it was a rare opportunity for these players to share their views directly with the President," he said, per Beck. "I am disappointed that that will not happen. More importantly, I am proud of our players for taking an active role in their communities and continuing to speak out on critically important issues."
In a recent memo, Silver and NBPA executive director Michele Roberts pledged their resources and support to players seeking to make a difference in their communities, according to ESPN.com's Adrian Wojnarowski.
"Fortunately, you are not only the world's greatest basketball players -- you have real power to make a difference in the world, and we want you know that the Players Association and the League are always available to help you figure out the most meaningful way to make that difference," the memo read.