Mickelson was one of the game’s most popular players when, at the age of 51, he became the oldest man to win a major with victory at the 2021 US PGA Championship at Kiawah Island.
He was a fan favourite with an affable demeanour and daring style of play. He was regarded as a family man who attracted big money sponsorship deals, a marquee player at every tournament where he competed.
But he was subsequently embroiled in a number of controversies. The 55-year-old was among the first recruits to LIV Golf, despite making derogatory comments about the Saudi Arabian backers of the breakaway tour.
In the wake of those inflammatory quotes, published by journalist Alan Shipnuck, Mickelson took himself away from the game, missing the 2022 Masters and the defence of his US PGA title.
He reappeared at LIV’s inaugural event at the Centurion Club near Hemel Hempstead in June 2022. “I’ve said and done a lot of things that I regret,” Mickelson said to reporters at his pre-tournament press conference.
“I’m sorry for that and sorry for the hurt it caused a lot of people.”
As well as being a central and divisive figure in golf’s civil war, prompted by LIV’s emergence as a rival to the PGA Tour, Mickelson was also embroiled in controversy away from the course.
He was involved in a US federal investigation into insider trading that led to the imprisonment of one of his friends, Billy Walters.
The American bookmaker then alleged in a book published after his release that Mickelson had waged a billion dollars in sporting bets.
Such stories of excessive gambling prompted the charismatic left-hander to say: “I have also been very open about my gambling addiction.
“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 has played only one LIV tournament this year, in South Africa, missing the rest of their schedule to prioritise “a family health matter”.
This absence from competitive golf is not thought to relate to the alleged incident at the Farms Golf Club.
He missed this year’s Masters and US PGA despite being eligible for both majors. He will not play at next week’s US Open, an event where he has been runner up six times. It is the only major he has yet to win.
That championship is being staged at Shinnecock Hills, where in 2018 Mickelson stunned fans by hitting his ball while it was still rolling to prevent it leaving a green.
It was an unprecedented incident in top level golf and while he was penalised two shots, many observers believe he should have been thrown out of that tournament.
This latest alleged incident is more serious and provides another hit to his reputation.
The Farms is located 25 miles northeast of San Diego close to where Mickelson grew up.
An ultra exclusive country club, it was a long-time base for the 45 time PGA Tour winner, somewhere he relied on to prepare his game for the biggest tournaments.