The apology comes after some initial defiance on the matter from Mickelson. While Mickelson was already well behind the tournament's leaders at that point, more than a few observers felt that he was guilty of cheating, rather than simply having harmlessly given into frustration, and should have withdrawn or been disqualified.
When asked if Mickelson's actions could prompt a rule change, Lee said: "I don't think so". "I gladly take the penalty". It's my understanding of the rules.
"I have had multiple times where I've wanted to do that", he said. As his bogey putt on the par-4 was going by the cup, he decided he didn't want to play "Army golf" (left, right, left, right) and whacked it back toward the hole.
A putt rolled past the hole and was going downhill.
USGA chief executive Mike Davis later revealed that Mickelson had telephoned him to clarify whether or not he should have been disqualified.
Mickelson eventually finished the tournament in a tie for 48th place, 15 shots behind victor Brooks Koepka.
Davis said: "Phil really did want to understand how the rule operates because he didn't want to... frankly, as he said to me, he goes, "Mike, I don't want to play in this championship if I should have been disqualified". Again, note that the last line in Rule 14.5 says Rule 1.2 becomes the law of the land if the ball is purposely deflected or stopped. He played a moving ball'. This heinous act of selfishness and disregard for the rules brought forth the penalty of the United States Professional Golf Association's Rules of Golf Rule 14-5. Ultimately, he got the ball in the hole, but had to take a two-stroke penalty for hitting a moving ball, He ended up with a ten on the hole.
'You might have a bad day at work or do something or say something that you regret. Mickelson said. "It's amusing". "I'm sorry that you're taking it that way, it's certainly not meant that way".
If Mickelson had a bad moment on the 13th green during his third round, his final round brought a much happier occasion.
There was a moment of levity on the final day when Mickelson returned to the scene of the "crime", the 13th green, and made a par four.
"He should have come out and said "Hands up, this course has got me this week - I just lost it". To his wife, though, it was no more than an "uncharacteristic" incident.
"I think he has done himself a disservice".