Charley Hull and Georgia Hall have pulled out of this week's Hanwha Lifeplus International Crown team event at Harding Park in San Francisco.
The duo were listed in the field for the biennial LPGA match play tournament that sees eight four-person international teams compete in a round-robin group stage, with the top two from each qualifying for the semi-finals.
Hull and Hall were part of the English team alongside Jodi Ewart Shadoff and Bronte Law before withdrawing due to illness and injury respectively and will now be replaced by Alice Hewson and Liz Young.
Hull, the World No. 18, said: "I've been quite sick the past couple of weeks with stomach issues. I was hoping I could play through it but it seems not and I'm going to need to seek some help.
"I'm really sorry to let the tournament down and of course my team-mates."
Hall added: "I've been struggling with my foot for the past few weeks and in spite of daily physio treatment it's not improving, so I've been advised to take a week off. I'm really sorry not to be able to play and wish my England team-mates the best of luck."
England start the fourth edition of the International Crown tournament as the fifth seeds and have been drawn in Group A with the United States, Sweden and China, while Group B is made up of South Korea, Japan, Thailand and Australia.
Each country will play two four-ball matches against the other three countries in their pool across the first three days to determine who advances, with the semi-finals and final consisting of two singles ties and one foursomes match.
