The pro golfer Phil Mickelson faced a mounting backlash this week for his reported remarks about a Saudi-backed golf tour, with a biographer quoting him as saying that though he knew of the kingdom’s “horrible record on human rights,” the tour was a “once-in-a-lifetime” opportunity.

Mickelson, a six-time major winner, made the comments during a nearly hourlong phone interview last November, Alan Shipnuck, a longtime golf writer who is completing a biography on the golfer, said on Friday.

A former writer for Sports Illustrated and Golf Magazine, Mr. Shipnuck reported the remarks on Thursday on The Fire Pit Collective, a golf site.

Mickelson, 51, had been asked to comment about his connection to the Super Golf League, an upstart tour whose main source of funding is the Public Investment Fund of Saudi Arabia, a sovereign wealth fund totaling more than $400 billion.

He called the Saudi authorities “scary,” using a profanity to describe them, and noted the murder of Jamal Khashoggi, the Washington Post journalist who was assassinated in 2018 with the approval of the kingdom’s crown prince, according to U.S. intelligence officials. Mickelson also alluded to the criminalization of homosexuality in Saudi Arabia, where it is punishable by death.

“We know they killed Khashoggi and have a horrible record on human rights,” Mickelson was quoted as saying by the biographer. “They execute people over there for being gay. Knowing all of this, why would I even consider it? Because this is a once-in-a-lifetime opportunity to reshape how the PGA Tour operates.”

Representatives for Mickelson, who is one of the biggest names linked to the breakaway tour, and the Saudi Embassy in Washington did not immediately respond to a request for comment on Friday.

A spokesman for the PGA Tour declined to comment on Friday.

When reached on Friday, Mr. Shipnuck said that the golfer had previously declined to be interviewed for his biography, “Phil: The Rip-Roaring (and Unauthorized!) Biography of Golf’s Most Colorful Superstar,” which is scheduled to be published in May. But he said that Mickelson had granted him an on-the-record interview in an attempt to explain his potential involvement in the breakaway tour.

“Phil likes to play with fire,” Mr. Shipnuck said. “Sometimes when you play with fire, you’re going to get scorched. I don’t think he realized how hot this topic is with Saudi Arabia.”

In his online account of the interview, Mr. Shipnuck said that the golfer had enlisted three other unidentified players to hire lawyers to draft the upstart tour’s operating agreement.

Several top golfers criticized Mickelson for his remarks, including Justin Thomas, the eighth-ranked player in the world. Speaking to reporters on Thursday at the Genesis Invitational near Los Angeles, he said it “seems like a bit of a pretty, you know, egotistical statement.”

Thomas continued: “It’s like he’s done a lot of great things for the PGA Tour, it’s a big reason it is where it is, but him and others that are very adamant about that, if they’re that passionate, go ahead. I don’t think anybody’s stopping them.”