– One of the appeals of the U.S. Open is watching the world's best golfers act like the rest of us. On Saturday at Shinnecock Hills, Phil Mickelson took that to an absurd extreme that shocked a sport serious about its rules and decorum.

On the 13th hole of the third round — and on his 48th birthday — one of the best golfers of his era ran down an errant putt and hit it back toward the cup before it had stopped moving, drawing a two-stroke penalty for a score of 10.

He finished his day 11 over par with an 81 and is 17 over for the tournament, far out of contention but in the thick of every golf fan's conversation.

Mickelson later insisted his maneuver strictly was strategic, not a result of mounting frustration — either with himself or the course setup. After emerging from a long visit to the scorer's hut, he rejected the notion the incident might harm his reputation.

"I don't see how," he said. "If somebody's offended by that, I apologize to them, but toughen up. It's not meant that way. I simply wanted to get onto the next hole."

The nuttiness began when Mickelson's bogey putt on the par-4 13th missed right, rolling off toward parts unknown. He jogged to catch up to it, then swatted the ball back uphill and nearly holed it. That was shot No. 6.

After that his putt for triple-bogey lipped out, he tapped in for an eight — plus the two-stroke penalty.

"The ball was going to go off in a bad spot," he said. "I didn't feel like continuing my display, and I'll gladly take the two-shot penalty and move on."

Mickelson said he had been tempted to use that strategy before and probably should have at times at the Masters, "on 15, when the ball years ago would go off into the hazard. That would have saved me a shot or two back then."

John Bodenhamer, the United States Golf Association's senior managing director of championships and governance, said Mickelson was penalized under Rule 14-5, which forbids hitting a moving ball.

Rule 1-2 calls for disqualification if a player breaks a rule to give himself a competitive advantage. Bodenhamer said the rules committee "mobilized quickly and unanimously decided this situation is specifically and explicitly covered under Rule 14-5."

Had Mickelson stopped the ball rather than hitting it while it was in motion, he might have been kicked out of the tournament. "The fact that we dealt with was that he made a stroke at a moving ball," Bodenhamer said.

After the hole, Mickelson was seen laughing with his playing partner, Andrew "Beef" Johnston, who shot 82 in the third round.

"I looked at him and I was like, 'Is this actually happening?' " Johnston said. "I looked at him and I said, 'Sorry, but I can't help but laugh at that.' It's one of the funniest things I've ever seen . It's something you might see at your home course with your mates or something. I think it's just a moment of madness."

Said Mickelson: "I mean, how can you not laugh? It's funny. It's part of the U.S. Open. It's just funny. I didn't mean it disrespectfully. If you're taking it that way, look, I'm sorry, that's not the way it's meant."