Phil Mickelson’s gambling exploits are detailed in a new book set to hit shelves later this month.

Mickelson is alleged to have bet more than $1 billion on various football, basketball and baseball games over the last 30 years and allegedly asked his associate to place a $400,000 wager on the U.S. team to win the Ryder Cup in 2012, according to details in the book called “Gambler: Secrets from a Life at Risk.”

Mickelson’s associate at the time, Billy Walters, is the author of the book. An excerpt from it was published in Golf Digest and Fire Pit Collective. Walters, who is believed to be one of the most successful American gamblers ever, writes extensively about his relationship with Mickelson.

Phil Mickelson on the second day of the LIV Golf Greenbrier at The Old White Course on Aug. 5, 2023, at White Sulphur Springs, West Virginia. (Joe Robbins/Icon Sportswire via Getty Images)

Walters wrote that he and Mickelson had a partnership starting in 2008 that lasted about five years. Walters wrote that Mickelson had two offshore betting accounts at the time that would take “big action.” He added that “Lefty’s” betting limits for college football and NFL games were $400,000 per sport.

In one instance, Walters wrote that Mickelson called him about making a bet on the U.S. team for the Ryder Cup. Mickelson was on the squad with Tiger Woods and Bubba Watson and appeared to be confident about the team’s win.

“’Have you lost your f—ing mind?’” Walters says he asked Mickelson. “’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.’”

Mickelson replied, “alright,” and it was unclear whether he ever made the bet. Team Europe won the match by one point.

Billy Walters, owner of Walters Golf, exits federal court in New York, on April 6, 2017. (Louis Lanzano/Bloomberg via Getty Images)

Walters added that “they said it was nothing for Phil to bet $20,000 a game on long-shot, five-team NBA parlays. Or wager $100,000 or $200,000 a game on football, basketball, and baseball.” Citing his own “detailed” records and “additional records” from sources, Walters provided a look into Mickelson’s gambling habit between 2010 and 2014.

Walters believes Mickelson wagered more than $1 billion over the course of 30 years. He wrote that Mickelson’s gambling losses are estimated to be about $100 million. He says Mickelson in 2011 made 3,154 bets – about nine wagers per day. In a single day in June of that year, Walters says Mickelson made 43 bets on MLB games and took more than $143,000 in losses.

Mickelson’s reps didn’t immediately respond to Fox News Digital’s request for comment.

Phil Mickelson reacts as he walks off the tee box at the seventh hole during the LIV Golf Greenbrier at The Old White Course on Aug. 4, 2023, at White Sulphur Springs, West Virginia. (Joe Robbins/Icon Sportswire via Getty Images)

Mickelson’s gambling habit has been in the public view over the last near decade. Court documents in 2015 revealed nearly $3 million was transferred from Mickelson to a third party as part of an “illegal gambling operation,” according to ESPN. He was reportedly linked to an alleged mob bookie in 2007.

He was not charged in any of those cases.

Walters and Mickelson were linked in an insider-trading scandal in 2014. Walters was convicted on conspiracy, securities fraud and wire fraud charges in 2017. Mickelson did not testify at the trial and was not charged in the matter and later settled a civil case with the SEC and agreed to surrender the profits he made from trades, according to Golf Digest.

Walters insisted in his book that he never told Mickelson that he had insider information

Mickelson opened up to Sports Illustrated about his gambling in 2022 when asked about why he joined LIV Golf after years on the PGA Tour.

“My gambling got to a point of being reckless and embarrassing,” he said. “I had to address it. And I’ve been addressing it for a number of years. And for hundreds of hours of therapy. I feel good where I’m at there. My family and I are and have been financially secure for some time.

Phil Mickelson plays a shot during a practice round prior to The 151st Open at Royal Liverpool Golf Club on July 19, 2023, in Hoylake, England. (Stuart Kerr/R&A/R&A via Getty Images)