Australia batter Steve Smith was ruled out on the morning of the crucial third Ashes Test against England and replaced by Usman Khawaja.
Smith missed training on Monday because of illness, then was struck in the groin when he batted in the nets on Tuesday morning.
The 36-year-old was on the outfield at the Adelaide Oval before play began, only to leave the stadium before the toss took place.
“Steve has been feeling a little bit unwell over the past couple of days,” said Australia captain Pat Cummins.
“He gave it a crack this morning, but didn’t think he was going to get up for this one. He’s headed off home.
“We’re pretty lucky we’ve got someone like Usman who can step right in.”
Khawaja, who was left out of the Australia XI when it was named on Tuesday, comes in to take Smith’s place at number four.
Australia, 2-0 up after wins in the first two Tests, will retain the Ashes if they avoid defeat in Adelaide. The hosts won the toss and chose to bat first.