Phil Mickelson will skip the US Open later this month as the tournament clashes with his daughter's graduation.
The 46-year-old, who has never won the US Open, says his daughter Amanda's high school graduation will take priority over the only major tournament he has failed to capture.
Despite notifying officials of his intention, the American has yet to officially withdraw and has up until the start of his opening round to pull out.
"My daughter is graduating, she is the school president, she'll be giving the commencement speech for the school and I am going to be there," Mickelson said at the Memorial Tournament press conference.
"Unfortunately it comes on the Thursday of the Open, around 10 in the morning pacific time and there's no way I can make it no matter what the tee time is.
"I didn't want the USGA (US Golf Association) to be caught off guard and I wanted the alternate to know he will most likely be in.
"There is no sense in doing it (withdrawing formally) now. Something might come up with the commencement, the weather, something unforeseen, but it doesn't look very good. I wanted to make sure they had enough notice.
"It doesn't look good for me playing but I am really excited about this moment in our family's life."
In a statement, the USGA accepted Mickelson's decision and said: "Phil called to say because of the timing of his daughter's high school graduation, he would likely not be able to play in the US Open at Erin Hills.
"We applaud and appreciate the fact that he is being pro-active so that the USGA can make any appropriate adjustments should he not be able to play.
"We certainly understand and support that Phil's family commitments are of paramount importance, and hope that the timing will work in his favour."
The US Open runs from June 15-18 at Erin Hill.
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