Some Chinese online retailers appear to have pulled Houston Rockets merchandise off their websites amid an ongoing controversy over comments made by a team executive expressing support for Hong Kong protesters. A search for "Houston Rockets" merchandise on Alibaba-powered Tmall, as well as competitors JD.com and Suning, yielded no results, a finding reported by Quartz and confirmed by CBS MoneyWatch.

The Houston Rockets have enjoyed an enormous following in China largely because basketball player Yao Ming once starred for the Texas team. Yao, now president of the Chinese Basketball Association, cut ties with his former team following the outcry in China from Rockets general manager Daryl Morey's since-deleted tweet.

Morey had tweeted an image that read, "Fight for Freedom. Stand with Hong Kong," referring to the four-month-old protests in the semi-autonomous Chinese territory.

A search for "Houston Rockets" on top Chinese ecommerce site Tmall produces no results.

A search for "Houston Rockets" on JD.com returns no results.

Merchandise for other NBA-affiliated teams does not appear to have been wiped from the websites. On Tmall, the official NBA landing page did not have any items for sale from the Houston Rockets, but it listed sports jerseys and pants for teams like the Golden State Warriors and the Boston Celtics. A search for the Los Angeles Lakers returned dozens of results on Tmall, as well as more than 300 related products on JD.com.

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Alibaba did not return a request for comment.

But a search on Tmall for Los Angeles Lakers merchandise returns dozens of results.

The outcry following the initial tweet illustrates the fine line U.S. businesses must walk with the Chinese government, especially those with multi-billion-dollar aspirations for the vast Chinese market.

China consumers are especially important for sales of American sports brands. While basketball shoe sales have declined in the U.S. in recent years, they've grown in China, where endorsements by NBA players still drive sales, according to market research company NPD Group.

Nike's North American sales have faltered, declining in 2018 for the first time in five years. But the company's sales in China have seen double-digit percentage growth in each of the past five years. In its latest fiscal year, China brought in $6.2 billion in revenue for the brand, a 21% increase from the year prior, out of $39.1 billion in global sales.

Under Armour has also seen its North American sales decline for the past three years, while its Asian Pacific sales have accelerated over the same time period.

"If Chinese kids stop buying western basketball shoes, I see the investments in athlete endorsements being worth even less," Matt Powell, senior sports industry adviser at NPD Group, wrote in a blog post. "The same goes for NBA licensed products; if Chinese kids stop wearing NBA jerseys, the sales and investments in the licenses will, in my opinion, likely be in jeopardy."