On the site Firepit Collective, Shipnuck presents an excerpt from the biography, which will be published on May 17.

There he writes about the discovery from documents from US authorities, which made an investigation into Mickelson in 2014 when the golf star was accused of insider trading on the stock exchange.

Authorities found that Mickelson had lost over $ 40 million (approximately $ 400 million) between 2010 and 2014. During those years, Mickelson earned more than $ 40 million a year on golf, but he also made a huge amount of money through his extravagant lifestyle. with private jet, large house, caddy, trainer and a personal chef.

He even bought a Tyrannosaurus Rex skull as a birthday present.

Did not pay the caddy

Add to that a $ 10 million gamble annually.

Shipnuck believes that Mickelson during those years at best went up financially, but he may even have gone backwards.

"And Mickelson's income dropped significantly between 2014 and 2017 when he did not win anything," writes Shipnuck.

A lousy economy also seems to have been behind the longtime caddy Jim Mackay leaving Mickelson in 2017. According to Shipnuck, Mickelson was behind with salary payments to Mackay of millions of kronor.

Is he defending the title?

The money situation may also partly explain Mickelson's flirtation with the new Saudi Arabia - backed and money-loving golf tour that starts in June.

The 51-year-old, who also wanted to criticize the PGA Tour by his approach to the controversial LIV tour, received harsh criticism over his statement earlier this year:

- We know that the (Saudis) murdered (journalist Jamal) Khashoggi and that their human rights history is terrible.

They execute people there because they are gay.

When I know all this, why should I even consider it?

Because it's a "once in a lifetime" opportunity to change the way the PGA Tour works, Mickelson said.

After the statement, he was forced to take a timeout from golf.

The first big question now is whether Mickelson intends to defend his PGA Championship title later in May.

The major competition starts on 19 May.

Two days earlier, the book about Mickelson was released, which could create a lot of uproar and demands for comments from the American.

The other big question is whether Mickelson will play in the LIV Tour's first competition in London on June 9-11.

According to the BBC, the PGA Tour and the European Tour can give players permission to participate in that competition, but not in the later competitions in the United States.