Phil Mickelson, who stirred outrage from golf purists last weekend after hitting a moving ball during the third round of the U.S. Open, issued an apology on Wednesday, saying, "My anger and frustration got the best of me."

In a text message to several national golf writers, Mickelson wrote:

"I know this should've come sooner, but it's taken me a few days to calm down," he said. "My anger and frustration got the best of me last weekend. I'm embarrassed and disappointed by my actions. It was clearly not my finest moment and I'm sorry."

The incident occurred Saturday on the 13th green at Shinnecock Hills Golf Club when Mickelson putted past the hole and ran toward the ball as it was gathering speed down a slope. He then hit the ball before it stopped, sending it by the hole back to where he originally putted from.

The U.S. Golf Association assessed Mickelson a 2-stroke penalty under Rule 14-5 of the Rules of Golf, which gave him a score of 10 on the hole. However, the USGA elected not to disqualify Mickelson for committing a serious breach of the rules.

Mickelson, seeking his first U.S. Open championship after six second-place finishes, completed the round with an 81. Later, he called Mike Davis, the CEO of the USGA, and told him, according to Davis, "Mike, I don't want to play in this championship if I should have been disqualified.

"It was us applying the rules," Davis said. "That's different than if he had deliberately just stopped the ball or whacked it in another direction or something like that."

After he completed Saturday's round, Mickelson told reporters he meant no disrespect, that he was merely taking advantage of the rule.

"If somebody's offended by that, I apologize to them, but you know, toughen up, because this is not meant that way," he said. "It's just simply I just wanted to get on to the next hole and I didn't see that happening at the time. I'll gladly take my 2 strokes and move on."