The four-times Major champion hinted after last week's Humana Challenge he was considering making "drastic changes" because of soaring federal and state tax rates but has since said he should have kept his thoughts to himself.
"This reminds me a lot of Winged Foot in 2006, where I hit a drive way left off the tents," Mickelson said on the eve of this week's Farmers Insurance Open at Torrey Pines.
"So this happened to be way right, but way off the tents. You know, I've made some dumb, dumb mistakes, and, obviously, talking about this stuff was one of them."
Mickelson led the 2006 US Open by two shots with three holes remaining but fell back into a three-way tie for second after an aggressive approach at the last led to a double-bogey.
The American left-hander had hit the roof of a hospitality tent with his drive on 18, then bounced backwards off a tree with a three-iron for his second shot on the way to a closing 74.
"Seven years later, I realised I should have just wedged back," a smiling Mickelson said of his second shot on the final hole. "I could have tried to make a par from the fairway, and maybe made a bogey and at worst be in a Monday play-off."
"Like Winged Foot, where I tried to carve a three-iron around a tree and get it up by the green, I make double bogey and lose the US Open, I think I'm going to learn my lesson and take a wedge and get it back in play.
"I made a big mistake talking about this stuff publicly, and I shouldn't have done that," he added, again apologising for publicly venting his feelings about soaring tax rates for millionaires in his native California.
One of the most popular figures in the game, Mickelson signs more autographs for fans than most of his peers and is nicknamed "Phil the Thrill" because of his bold and, at times, outrageous shot-making.
However, he accepts that the comments he made on Sunday after he tied for 37th place at the Humana Challenge in his first US PGA Tour event of the season were, at best, polarising.
"It was insensitive to talk about it publicly to those people who are not able to find a job, that are struggling paycheque to paycheque," the 42-year-old said.
"I think that was insensitive to discuss it in that forum."
Mickelson, a 40-times winner on the US PGA Tour, has piled up career earnings of more than $67 million and considerably more via corporate endorsements and his golf course design company.
According to Forbes magazine, the American left-hander earned $43 million in endorsements in 2012, second only to Tiger Woods among golfers and seventh among all athletes.
"Well, it's been an interesting off-season," Mickelson said on Sunday. "I'm not going to jump the gun and do it right away, but I will be making some drastic changes.
"I happen to be in that zone that has been targeted both federally and by the state and it doesn't work for me right now."
California voters in November approved Proposition 30, which raised state income tax to 13.3 per cent on earnings of $1 million or more, a 29.13 per cent increase over the previous "millionaires" tax of 10.3 per cent.
Mickelson will also be affected by the rise in the top bracket of the federal tax code where rates have gone up from 35 per cent to 39.6.
Asked whether he might leave California for a state such as Florida or Texas which does not charge state income tax, he replied: "I don't have a plan formulated yet on what I'm going to do.
"And when I do come up with a plan, and (his wife) Amy and I have talked about it, and we've been working through this for a while, and I'll be able to talk more about it publicly then."