Nick Kyrgios and Alex de Minaur won't play in Australia's Davis Cup tie against Brazil next week because of injury.
Kyrgios has been battling a wrist complaint while de Minaur has aggravated an abdominal injury which sidelined him from last month's Australian Open.
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Australia's cup captain Lleyton Hewitt has summoned John Peers and Alex Bolt into his squad for the tie in Adelaide next Friday and Saturday.
Krygios withdrew mid-match at the ATP World Tour event on Wednesday in Acapulco, where de Minaur lost his first outing since early January.
"Both are disappointed, both guys love playing in the team environment and playing for Australia," Hewitt said on Friday.
"It's not an easy decision but at the end of the day you have got to go off the medical advice.
Kyrgios sidelined for two weeks
Both Kyrgios and de Minaur were included in Australia's squad which was announced prior to the Acapulco tournament.
"Both guys wanted to be named hoping that they would be fine to play," Hewitt said.
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"But as it has turned out, with Nick pulling mid-match, he has been struggling for a couple of weeks.
"And Alex, as that first match went on, he had probably come back a week or two too soon."
Hewitt was uncertain how long either would be sidelined for, but expected Kyrgios to be out for at least a fortnight.
"For at least the next week, two weeks, he shouldn't be picking up a racquet," he said.
The winner of Australia's tie against Brazil will qualify for the Davis Cup finals in Spain in November.