Defending champion Lilia Vu has withdrawn from the Chevron Championship prior to her first round at The Club at Carlton Woods.
Vu claimed her maiden Major title at the tournament last year in what was a breakout year for the American, who went on to win the AIG Women's Open at Walton Heath as she climbed to the top of the world rankings.
The 26-year-old, however, has been dealing with a back injury so far this season, which forced her to withdraw midway through the HSBC Women's World Championship and Blue Bay LPGA in successive weeks earlier in the year.
Vu was scheduled to tee off at 1.10pm local time alongside Nelly Korda and Minjee Lee in the first round but was replaced in the grouping by Jennifer Song after aggravating her back during her pre-round warm-up.
“I am so sorry to have to withdraw from The Chevron Championship, as I was really looking forward to defending my first major title," she said in a statement. "I have been dealing with a back injury for a while now. Some days are better than others, and today was unfortunately not a good day.
"During my normal warm-up routine, I had severe discomfort in my back and I felt that I could not compete up to my standards and made the decision to withdraw from the tournament ahead of my tee time. I am planning to return home to see my doctors immediately to determine the best appropriate next steps.
"I want to thank everyone at Chevron for their support and understanding. I am so proud to be a Chevron champion and can’t wait to get back next year. Thank you as well to the fans and volunteers at the course – you are in for a wonderful four days!”
Earlier in the week, the defending champion spoke about the disruptive start to her season due to her battles with injury but had hoped she was nearing full fitness ahead of her championship defence.
"It's been a rough couple months battling with my injury. It's been a little scary. I've definitely cried a lot on the range sometimes because my back just couldn't hold up," she said.
"I definitely feel a lot better than I did at PV and Phoenix. I would say we're basically 95 per cent there. If I stay healthy this week I think I'll be able to do what I need to do.
"It's been an up and down [season] not being fully physically healthy. On the days that I feel physically healthy, I'll get upset about not performing the way I think I should.
"It kills me that I can't go and train like fully the way I like to because that's something I love to do. I got back into it last week and was fine. I feel like I'm in a good area for this week."
The overwhelming favourite in Texas this week is current world number one Korda who has won her last four tournaments and is vying to become only the third player after Nancy Lopez and Annika Sorenstam to win five consecutive LPGA Tour events.
The 25-year-old got her first round underway on Thursday afternoon, with fellow American Lauren Coughlin setting the early pace after a superb six-under-par round of 66.
