Three years ago, journalists at Sports Illustrated were worried that the venerable magazine’s new owners and operators were drastically lowering its standards. They noted reports of plagiarism, and worried about substandard writing and the use of freelance reporters with little due diligence. The journalists also wanted better pay, greater transparency during the hiring process and a guarantee that all work published on the Sports Illustrated website would be edited.

It appears that things have not improved since then.

On Monday, the science and technology publication Futurism reported that Sports Illustrated had published product reviews under fake author names with fake author biographies. Futurism could find no evidence that the supposed authors were real, and the photographs with the bios could be found on websites that sell artificial intelligence-generated headshots. Futurism also raised the possibility that artificial intelligence had generated the words in the reviews.

“If true, these practices violate everything we believe in about journalism,” the union representing Sports Illustrated journalists said in a statement after the report was published. “We deplore being associated with something so disrespectful to our readers.”

The Arena Group, which publishes Sports Illustrated under a complicated management structure, blamed a vendor, AdVon Commerce, for the situation. Sports Illustrated licenses product reviews from AdVon, and AdVon assured the Arena Group that “all of the articles in question were written and edited by humans,” said Rachael Fink, an Arena Group spokeswoman. She added that AdVon “had writers use a pen or pseudo name in certain articles to protect author privacy.”

Arena has now ended its partnership with AdVon and is investigating AdVon’s assurances that artificial intelligence was not used to write the articles.

According to Arena, AdVon said it used “both counterplagiarism and counter-A.I. software.” But AdVon markets itself to potential customers as a company deeply involved in artificial intelligence. On LinkedIn, AdVon says it develops machine learning and artificial intelligence for e-commerce. A page for the candidacy of Ben Faw, AdVon’s co-founder and chief executive, for the board of directors for Harvard’s alumni association similarly describes AdVon as using machine learning and artificial intelligence.

Mr. Faw did not respond to requests for comment.

For more than a half century, Sports Illustrated was the standard-bearer in sports journalism. It was the home of sportswriting titans like Frank Deford and Dan Jenkins, and photographers like Walter Iooss and Jim Drake. Making the cover of the magazine or winning its Sportsman (later Sportsperson) of the Year award was the mark of a star, from Muhammad Ali to Naomi Osaka. The magazine’s extremely profitable swimsuit issue arrived like a cultural thunderclap year after year.

At its peak, Sports Illustrated had a print circulation of more than three million. The magazine has struggled, however, to adapt to the digital age. Monday’s revelation was just the latest sign of drift at Sports Illustrated, exacerbated by a relentless pursuit of engagement with the site’s non-journalistic entities.

“If you look at the magazine’s history, there’s just been a series of bad editorial decisions,” said Michael MacCambridge, a journalist and the author of 1997’s “The Franchise: A History of Sports Illustrated Magazine.”

In 2019, the media conglomerate Meredith sold Sports Illustrated’s intellectual property to the Authentic Brands Group. It also sold a 10-year license to publish Sports Illustrated to TheMaven, which has since been rebranded as the Arena Group. According to financial filings, Arena pays Authentic Brands $15 million annually for the right to operate Sports Illustrated.

Authentic Brands’ business model mostly involves buying fashion brands that are down on their luck or in bankruptcy — Brooks Brothers, Aéropostale, Forever 21 — and then shedding legacy commitments, cutting costs and operating the brand while banking on its name recognition.

The Sports Illustrated brand has been attached to nutritional supplements, and the chief executive of Authentic Brands once envisioned Sports Illustrated-branded medical clinics.

Since 2019, there have been repeated rounds of layoffs at Sports Illustrated and reductions in the circulation of the print magazine. Hundreds of sites dedicated to individual teams — helmed by non-staff writers paid small sums — were created with little oversight and diluted what it meant for “Sports Illustrated” to write something.

Sports Illustrated’s problems began before Authentic Brands and Arena. Under its original owner, Time Inc., there were layoffs — including the last remaining staff photographers at a publication celebrated for its sports photography — and it went from being a weekly print magazine to a monthly.

But the stewardship by Authentic Brands and Arena has been particularly rocky. Because Authentic Brands retains the rights to Sports Illustrated’s brand, Arena’s options for generating revenue are somewhat limited, encouraging a daily churn of articles. Employees have complained publicly that Arena has been dismissive of concerns about article quality and a lack of editors — made worse in February when 17 members of the staff were laid off — all while enforcing weekly quotas from writers.

Last month, the newspaper publisher Gannett found itself in a situation very similar to Sports Illustrated’s. Product reviews on a site that Gannett owns, Reviewed, looked suspiciously like articles not written by humans, and nobody who works for Reviewed recognized the purported authors. A spokeswoman for Gannett said the articles had been “created by third-party freelancers hired by a marketing agency partner, not A.I.” That marketing agency partner was AdVon.

G/O Media, CNET and The Columbus Dispatch in Ohio have also experienced controversies related to publishing articles written by computers without adequate human oversight. The Associated Press, whose policies are often adopted as standards throughout the news industry, recently released its own artificial intelligence guidelines. They say that any output from A.I. tools should “be treated as unvetted source material,” and that The A.P. would not use images generated by artificial intelligence.