The claim is then made that in 2017 Jim Mackay left his role as Mickelson's long-time caddie partly because of hundreds of thousands in unpaid wages. An insider has since confirmed this to Telegraph Sport.
There have long been rumours of Mickelson's betting habits, as well as other indiscretions, and these revelations will inevitably only shine the spotlight ever brighter on the beleaguered left-hander.
The book is due to be released on May 17, just two days before the first round of the US PGA and this is just one factor why there is a growing belief inside the locker room that, despite being the reigning champion, the 51-year-old will not play in the season's second major.
Mickelson has been on indefinite leave from golf for almost three months since the initial furore broke out of material in Shipnuck's account.
Mickelson declared that the Saudis were "scary motherf-----s to be involved with" and referenced their "horrid human rights record", including the murder of journalist Jamal Khashoggi and the treatment of homosexuals.
But he figured that he could overlook all this because "it provides a once-in-a-lifetime opportunity to reshape how the PGA Tour operates."
Greg Norman, the Australian entrusted with overseeing the Saudi bid to revolutionise the professional male game, later told Telegraph Sport that Mickelson's comments and the resulting outrage derailed what had been the imminent launch of the breakaway league, but the plans were quickly redrawn and the US$255million eight-event LIV Golf Invitational Series will begin in St Albans next month, before heading to the US.
Mickelson has applied to the PGA Tour for a release to play in the tournament at the Centurion Club and will learn on Monday if he has been successful, as will others such as Lee Westwood, Sergio Garcia and Ian Poulter.