Golf fans who tuned in to the U.S. Open this weekend got much more drama than they were expecting.

A dramatic and bizarre move by Phil Mickelson at the 13th green kicked off a huge debate, and very nearly got the veteran golfer disqualified.

"A moment of madness"

With five major championships under his belt, Phil Mickelson is no stranger to the golf course or the rules of the game.

So fans were left scratching their heads when Lefty hit a moving ball on the 13th green at Shinnecock Hills in New York on Saturday.

Mickelson was putting for bogey when his shot went wide, and the golfer stunned fans by jogging around the ball to knock it back from the edge of the green.

His gobsmacked partner, Andrew Johnston, called the incident "a moment of madness."

Mickelson, who left the green smiling and laughing, was the only person on the course who didn't seem stunned by his action.

"How can you not laugh?" he told reporters. "It's funny."

It turns out the reason for Mickelson's knowing smile was a rule he thought would give him an advantage.

"Phil really did want to understand how the rule operates"

Mickelson later explained that he thought putting the moving ball would give him an automatic two stroke penalty.

The golfer reasoned that he would get off the green faster with the penalty than by putting from off the green, and says he's been dreaming of the tricky move for some time.

"I've had multiple times where I've wanted to do that," he said. "I just finally did."

"It's meant to take advantage of the rules as best as you can... I would gladly take the two shots over continuing that display."

But while Mickelson did get a two stroke penalty, he came very close to being disqualified.

If officials thought Mickelson was trying to get a clear advantage, he could have been ejected from the tournament on the spot.

The crucial detail, according to the USGA, is that Mickelson putted the ball back towards the hole, instead of trying to redirect it.

"Phil really did want to understand how the rule operates," said the association's chief executive Mike Davis.

"Because he didn't want to"”frankly, as he said to me: 'I don't want to play in this championship if I should have been disqualified.'"

Phil tells fans to "toughen up"

Plenty of golf fans are upset by the decision, and say that the Mickelson should have faced the music for his mistake. Or at least shown some remorse.

Mickelson's wife, Amy, at least hinted that he felt bad about the double putt.

"You know it's not his finest moment," she told reporters, "but hopefully he'll learn from it."

"Like anybody, good people make mistakes. We all have a moment in life sometimes and that was kind of a moment I think for him."

But Mickelson, who could face more fines and citations from the PGA Tour, is not ready to say sorry about his breach of the rules.

"If somebody's offended by that, I apologize," he said. "But toughen up."

Can you blame Mickelson for his actions, or do you see things from his point of view?

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[H/T: Golf.com, Golf Digest, Bleacher Report]