Britain's Charley Hull will have to overcome a recurring wrist injury if she is to go one better than last year and win her first major title in the ANA Inspiration.
Hull finished second to Lydia Ko at Mission Hills Country Club in Rancho Mirage last year, the world number one making a birdie on the 72nd hole to win by a shot.
Ko missed only her second cut in 95 LPGA events in last week's Kia Classic, where Hull was unable to play after aggravating her wrist when hitting a shot out of the rough.
"It's like a chip out of the bone and I inflamed it," the 21-year-old said. "I should be fine to play this week. I will sleep with it strapped and do everything else except golf with it strapped, but when I play I will take it off."
Ko's form is under the spotlight after she changed her caddie, coach and equipment at the end of last year, with her position on top of the rankings under threat after eight months without a win.
If world number two Ariya Jutanugarn wins this week, Ko's run at number one will end after 75 consecutive weeks. Jutanugarn was two shots clear with three holes to play 12 months ago, but bogeyed the last three holes.
"There is pressure because you're the number one ranked player, you should play awesome week in and week out, try and win every week," Ko told a pre-tournament press conference.
"But almost if you were second every week, I think you'd probably be the number one ranked player anyway. I think that's the big thing - it's more about consistency and how many times you can put yourself in contention and then sometimes being able to pull it off."
