Phil Mickelson has wagered more than $1 billion over the last three decades and wanted to place a $400,000 bet on the 2012 Ryder Cup while playing for Team USA, according to a much-anticipated book by renowned gambler Billy Walters.

Mickelson denied ever betting on the Ryder Cup.

“While it is well known that I always enjoy a friendly wager on the course, I would never undermine the integrity of the game,” Mickelson said in a statement Thursday.

The stunning betting estimates Walters provides – from his own detailed record and from what he describes as two reliable sources – are detailed in an excerpt of Walters’ book, “Gambler: Secrets from a Life of Risk.”

The book is scheduled to be available on Aug. 22. The Fire Pit Collective obtained the excerpt.

Walters is widely regarded as America’s most famous gambler and claims to have a winning streak of more than 30 straight years.

He said he ended his betting partnership with Mickelson in 2014. Two years later, Walters was indicted in an insider trading case that partly involved stock tips prosecutors said he illegally passed to Mickelson. Mickelson was never charged but had to repay about $1 million he made off a stock deal. Walters was convicted and sentenced to five years in prison. He claims he could have avoided prison if Mickelson had told a “simple truth.”

Walters said he never told Mickelson he had inside information on Dean Foods stock, and he believed that Mickelson could have helped him by testifying.

“All Phil had to do was publicly say it. He refused,” Walters wrote. “The outcome cost me my freedom, tens of millions of dollars and a heartbreak I still struggle with daily. While I was in prison, my daughter committed suicide – I still believe I could have saved her if I’d been on the outside.”

Walters said Mickelson told him he had two offshore accounts, and that Mickelson had limits of $400,000 on college games and $400,000 on the NFL.

He said based on his detailed record and additional records provided by sources, Mickelson’s gambling between 2010 and 2014 included:

• Betting $110,000 to win $100,000 on 1,115 occasions, and betting $220,000 to win $200,000 on 858 occasions. That alone comes out to just over $311 million.

• Mickelson in 2011 made 3,154 bets for the year, and on one day (June 22), he placed 43 bets on Major League Baseball games that resulted in $143,500 in losses.

• He placed 7,065 bets on football, basketball and baseball.

“Based on our relationship and what I’ve since learned from others, Phil’s gambling losses approached not $40 million as has been previously reported, but much closer to $100 million. In all, he wagered a total of more than $1 billion during the past three decades,” Walters wrote.

“The only other person I know who surpassed that kind of volume is me.”

In his statement, Mickelson said he has been open about his gambling addiction. In an interview with Sports Illustrated last year, Mickelson referred to it reaching a point of being “reckless and embarrassing.”

“I have previously conveyed my remorse, took responsibility, have gotten help, have been fully committed to therapy that has positively impacted me and I feel good about where I am now,” Mickelson said.

Walters said they met for the first time at the 2006 AT&T Pebble Beach Pro-Am, and formed a betting partnership two years later.

Most stunning to Walters, he writes in the excerpt, was a phone call from the Ryder Cup in 2012 at Medinah. He said Mickelson was so confident he asked Walters to bet $400,000 for him on the U.S. winning.

“I could not believe what I was hearing,” Walters wrote. “’Have you lost your (expletive) mind?’ I told him, ‘Don’t you remember what happened to Pete Rose?’ The former Cincinnati Reds manager was banned from baseball for betting on his own team. ‘You’re seen as a modern-day Arnold Palmer,’ I added. ‘You’d risk all that for this?’ I want no part of it.”

He said Mickelson replied, “Alright, alright.”

“I have no idea whether Phil placed the bet elsewhere. Hopefully, he came to his senses,” Walters wrote.

Europe rallied from a 10-6 deficit on Sunday, staging the greatest comeback by a visiting team. Mickelson and Keegan Bradley won three straight matches before Mickelson urged U.S. captain Davis Love III to rest them Saturday afternoon. Mickelson lost his singles match to Justin Rose, a pivotal moment in Europe’s comeback.

Rory McIlroy, at odds with Mickelson over the divide between the PGA Tour and LIV Golf, couldn’t resist a dig at Mickelson over the claims in the book.

“At least he can bet on the Ryder Cup this year because he won’t be part of it,” McIlroy said Thursday in Memphis, Tennessee, at the PGA Tour’s FedEx St. Jude Championship.

The PGA Tour suspended Mickelson in early 2022 for helping Saudi-backed LIV Golf recruit PGA Tour players. He signed with LIV for a bonus reported to be upward of $150 million.

Walters was so successful with his gambling operation that bookmakers often limited the amount of his wagers. He would partner with others who had larger limits. He wrote that his partnership with Mickelson was a 50-50 split.

“In all the decades I’ve worked with partners and beards, Phil had accounts as large as anyone I’d seen,” Walters wrote. “You don’t get those types of accounts without betting millions of dollars.”