Hunter was lapping up the prospect of a starring role in the competition's first tie in Australia since 2019, on the back of her inspiring run from qualifying to make the third round at the season's opening grand slam at Melbourne Park in January.
On the cusp of the world's top 100 and boasting an impressive 10-4 Cup record in singles and doubles, Hunter loomed as a key piece of the jigsaw for new captain Sam Stosur on Friday and Saturday.
But the 29-year-old has been ruled out of Friday's singles after rolling her ankle in the final stages of training on Thursday.
She will have scans later in the evening after what Stosur described as a "very serious" injury.
Daria Saville, initially overlooked for singles action on Friday despite being Australia's highest-ranked woman, will replace Hunter in the qualifier.
She will face world No.562 Marcela Zacarias on Friday.
The timing of the injury is especially painful for Hunter, with the world No.3 doubles talent well placed to feature prominently on the Paris clay for Australia in the Olympics, which begin in July.
"We're all rallying behind Storm and wishing her the very best," Stosur said.
Injury on the eve of the tie has robbed Storm Hunter of a Billie Jean King Cup homecoming. (HANDOUT/TENNIS AUSTRALIA)
Stosur had overlooked Saville for singles action, at least until Saturday's reverse singles rubbers, despite the 30-year-old boasting the highest ranking in the squad.
Picked for the first time since 2016, Arina Rodionova - ranked 103rd in the world - was nominated as Australia's No.1 at Thursday's draw, with Hunter (No.116) the hosts' No.2 player.
Having earlier this year become the oldest woman to crack the top 100 for the first time, the 34-year-old Rodionova will face Mexico's Giuliana Olmos in the first match on Brisbane's Pat Rafter Arena on Friday.
Saville, on the comeback from a 2022 anterior cruciate ligament tear, was as high as 20 in the world in 2017 and this week returned to the top 100, sitting 94th in the current rankings.
The winner of this weekend's qualifying tie will progress to November's 12-team finals tournament, with Australia chasing their first title since 1974.
Mexico are without their three highest-ranked singles players - including world No.100 Renata Zarazua, who qualified for this year's Australian Open to become just the second woman from her country to compete in Melbourne's main draw.
Olmos was the first Mexican woman to reach the top 10 in doubles or singles and is currently ranked 25th in the world, while Fernanda Contreras is the highest-ranked Mexican singles player in the squad at 402.
Mexico's Giuliana Olmos will face Arina Rodionova in the opening singles match in Brisbane. (Darren England/AAP PHOTOS)
But team captain Agustin Moreno has instead chosen world No.562 Zacarias as his No.1, the 30-year-old also set to partner Olmos in doubles.
Captains are able to select other players within the squad to compete in the reverse singles rubbers.
Long-time captain Moreno oversees Loyola Marymount University's tennis program in Los Angeles and says the squad, rich in college experience, will channel that exposure in Brisbane.
"Even when they're favourites, they've seen upsets and there's belief there could be an upset here," he said.
"We have nothing to lose.
"When you're excited and happy, there's no pressure (and) you play better."
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