Phil Mickelson apologized Tuesday for remarks about the US PGA Tour and Saudi backers of a proposed rival tour, saying he will "desperately need some time away" from golf.

The 51-year-old left-hander, winner of six major titles and the reigning PGA Championship titleholder, also lost long-time sponsor KPMG after issuing a lengthy apology on Twitter.

Author Alan Shipnuck released excerpts last week from his upcoming book about Mickelson, the US star calling the Saudis "scary" with a "horrible record on human rights."

"Knowing all of this, why would I even consider it?" Mickelson said about the potential for joining the Saudi tour.

"Because this is a once-in-a-lifetime opportunity to reshape how the PGA Tour operates," he said. "They've been able to get by with manipulative, coercive, strong-arm tactics because we, the players, had no recourse."

Mickelson was quoted as saying he was willing to work with the Saudi Golf League despite human rights issues because it would provide leverage to create change on the PGA Tour.

"I used words I sincerely regret that do not reflect my true feelings or intentions," Mickelson said Tuesday.

"It was reckless, I offended people, and I am deeply sorry for my choice of words. I'm beyond disappointed and will make every effort to self-reflect and learn from this."

Mickelson said off-the-record comments were shared out of context and that his actions "have always been with the best interest of golf."

Rory McIlroy was among many players who ripped Mickelson for his remarks, with Bryson DeChambeau and Dustin Johnson distancing themselves from the Saudi league last weekend in the wake of Mickelson's remarks being revealed.

"I have made a lot of mistakes in my life and many have been shared with the public," Mickelson said. "My intent was never to hurt anyone and I'm so sorry to the people I have negatively impacted.

"This has always been about supporting the players and the game and I appreciate all the people who have given me the benefit of the doubt."

Phil Mickelson issued an apology on Tuesday for his controversial remarks made about the US PGA Tour and Saudi backers of a new proposed golf league
Phil Mickelson issued an apology on Tuesday for his controversial remarks made about the US PGA Tour and Saudi backers of a new proposed golf league GETTY IMAGES NORTH AMERICA via AFP / DONALD MIRALLE

Still, Mickelson criticized the way the game is being guided -- without being specific.

"Golf desperately needs change, and real change is always preceded by disruption," Mickelson said in his apology statement.

"I've always known that criticism would come with exploring anything new. I still chose to put myself at the forefront of this to inspire change, taking the hits publicly to do the work behind the scenes."

Three-time Masters champion Mickelson became the oldest major winner in history last May at Kiawah Island when he won the PGA at age 50.

But he said pressure and stress have worn him down over the past decade and he needs a break from the tour grind.

"I have experienced many successful and rewarding moments that I will always cherish, but I've often failed myself and others too," Mickelson wrote.

"The past 10 years I have felt the pressure and stress slowly affecting me at a deeper level. I know I have not been my best and desperately need some time away to prioritize the ones I love most and work on being the man I want to be."

Mickelson said his experience with the Saudi LIV Golf Investments group was "very positive" and "I apologize for anything I said that was taken out of context."

He called those he worked with on the project "visionaries" and "supportive" people who "share my drive to make the game better."

Regarding his sponsors and business partners, Mickelson said, "I have given all of them the option to pause or end the relationship as I understand it might be necessary given the current circumstances."

A statement from KPMG said the global audit and tax advisory service and Mickelson "have mutually agreed to end our sponsorship effective immediately. We wish him the best."