British number one Johanna Konta will not play for her country in the Fed Cup this year as she looks to protect her body and extend her career.
Konta, 28, has only played one tournament since September's US Open because of a knee injury.
"I need to take care of my body and take some decisions which are not always easy," Konta told BBC Sport.
Fellow Briton Katie Boulter has also cast doubt on her participation in the team event this year.
"I haven't confirmed my status on Fed Cup at the moment," said Boulter, 23, who was the British number two before a stress fracture in her back.
"It is something I am going to focus on after the Australian Open."
Britain face a qualifier away to Slovakia on 7 February with a spot in the inaugural Fed Cup finals at stake.
Konta and Boulter were part of the Great Britain side that beat Kazakhstan last February to reach the World Group II stage for the first time in 26 years.
Boulter injured her back in the tie, playing through the pain to win her two singles matches, but barely playing for the rest of the year in consequence.
Konta, ranked 13th in the world, says managing her knee issue - a tendonitis-like inflammation - played a part in her decision. She made the call after discussing her plans with British captain Anne Keothavong at the end of last year.
"It is a tough decision because the Fed Cup has always been something close to my heart," said Konta, who will compete for only the second time in four months when the Australian Open starts on Monday.
"I've had some incredible experiences in my career so far in Fed Cup and I'm looking to hopefully have some more.
"I'm not retiring [from it] full stop, just for this season with it being an Olympic year. With the challenge I had at the end of last year it is to be able to hopefully have more Fed Cup seasons under my belt.
"Hopefully it will give me the longevity I want."
Konta is seeded 12th at the Australian Open, where she reached the semi-finals four years ago.
She starts her latest campaign in Melbourne against Tunisia's Ons Jabeur, who is ranked 85th in the world but can trouble opponents with her variation.
Of her current fitness, Konta said: "I'm getting there. It's not acute, it's something that is manageable and something that will continue to be managed for quite some time."
Boulter reached 86 in the world during February's Fed Cup tie, but has slipped to 317th having not played a match on the main WTA Tour since then.
She has a nightmare draw in Melbourne, facing Ukrainian fifth seed Elina Svitolina on Tuesday.
"I am completely free of pain, I'm in a good place physically and that's the main thing for me," Boulter said.
"Svitolina is an amazing player but I'm just happy to be on the court."
BBC tennis correspondent Russell Fuller at Melbourne Park
Johanna Konta has been virtually ever-present in the GB Fed Cup team since 2013, and her sabbatical will hit the team very hard.
The recent retirement of Slovakia's Dominika Cibulkova had made this very tricky away tie appear much more winnable.
The task of qualifying for April's extremely lucrative Fed Cup finals will now fall to Heather Watson, Harriet Dart and Katie Boulter. Although, as you have read, Boulter's participation is far from assured.
With the Tokyo Olympics taking place in July, the period between May's French Open and September's US Open is even more frenetic than usual.
And Konta is no doubt mindful of the stress a switch from the hard courts of Melbourne to the indoor clay of Bratislava could put on her knee.
But it's a huge blow to the team, just as they've finally clambered their way into the elite bracket.