Australian Open semi-finalist Johanna Konta has pulled out of the Great Britain team for this week's Fed Cup in Israel because of illness.
The 24-year-old says she has an "ongoing intestinal issue" that got progressively worse in Melbourne.
She added she had been advised by doctors that playing could exacerbate the condition.
"This comes as a big disappointment to me and I regret not being able to play," she said.
"I have represented GB every time I have been asked to and fully intend to play again given the opportunity in the future."
Captain Judy Murray and her team face Georgia and South Africa from Thursday in their bid to win promotion from Euro/Africa Zone Group 1.
"While it's obviously very disappointing, we still have a squad of players capable of winning through the group," Murray said.
"I have a couple of days to fill the fourth spot, and that gives two of our most promising teenagers Katie Swan and Freya Christie the chance to join Heather Watson and our doubles specialists Jocelyn Rae and Anna Smith in the team."
Christie is ranked 395, while 16-year-old Swan is 520 in the world.