Boston Celtics games were abruptly pulled from the Chinese internet on Thursday after a center on the team, Enes Kanter, said on social media that the country’s leader, Xi Jinping, was a “brutal dictator,” citing his government’s repressive policies in Tibet.

The incident could spell fresh trouble for the N.B.A. in China. The league has millions of devoted fans there but has also just spent two years mending its image in the country after a Houston Rockets manager tweeted support in 2019 for pro-democracy protesters in Hong Kong.

That tweet, by Daryl Morey, now an executive with the Philadelphia 76ers, was quickly deleted, though not before setting off an uproar in China. Sponsors in the country severed ties and the state-run broadcaster stopped airing games, leading to financial fallout that the league estimated cost it hundreds of millions of dollars.

Geopolitical tensions and rising nationalism have made China a minefield for multinational companies, whose access to the country’s 1.4 billion consumers is often contingent on not taking the “wrong” stance on issues such as Beijing’s rule in Hong Kong, Tibet and Xinjiang.

An N.B.A. representative did not immediately respond to a request for comment.

In a video that was posted on Facebook, Twitter and Instagram on Wednesday, Kanter spoke into the camera for nearly three minutes and decried what he called a “cultural genocide” in Tibet.

“I say, ‘Shame on the Chinese government,’” he said, wearing a T-shirt with the image of the Dalai Lama, whom Beijing considers a criminal separatist. “The Chinese dictatorship is erasing Tibetan identity and culture.”

Another social media post by Kanter on Wednesday showed off sneakers emblazoned with Tibetan flag motifs and the words “Free Tibet.”

By Thursday, recent Celtics games were marked as unavailable for replay through Tencent, the Chinese internet giant that has partnered with the N.B.A. to stream its games in the country. The website for Tencent Sports also indicated that upcoming Celtics games would not be livestreamed.

Tencent Sports has not been livestreaming games with the 76ers, either. The team hired Morey last year as president of basketball operations.

A Tencent spokeswoman declined to comment.

On the Chinese social platform Weibo, a Celtics fan account declared that it would immediately stop posting about the team.

The account told its 615,000 Weibo followers: “Resolutely resist any behavior that damages national harmony and the dignity of the motherland!”

China considers Tibet part of its historical empire, though the authorities have long confronted protests against their rule there. The Communist Party under Mr. Xi has intensified efforts to defray ethnic tensions by encouraging the region’s residents to assimilate into Chinese society and making Mandarin Chinese the dominant language in public life.

Kanter, who is of Turkish heritage, has been an outspoken critic of Turkey’s president, Recep Tayyip Erdogan. Turkish prosecutors have sought Kanter’s arrest, and his Turkish passport has been revoked. He has expressed concern that Turkish agents might kill him overseas.

Elsie Chen contributed reporting.