Scans on Kurtley Beale are expected to confirm the recalled Wallabies veteran has ruptured his achilles, possibly bringing an end to his rugby career.
The 35-year-old, who was last week announced in Joe Schmidt's maiden 38-man squad, was helped from the field during a Sydney club rugby match on Saturday.
The utility back came off the bench for Randwick against Eastern Suburbs but went down untouched in the back-field.
A Wallabies spokesman said Beale would go for scans on Monday.
Beale was in line to make his return to the national side and add to his 95-Test career, having last played for the Wallabies in 2021.
Australia's first Test under new coach Schmidt is against Wales on Saturday at Allianz Stadium in Sydney, with a second match in Melbourne on July 13.
The Wales double-header will be followed by a one-off Test against Georgia in Sydney on July 20.
It's understood Beale was permitted to turn out for Randwick after being told he wouldn't face the Welsh next weekend.
He had returned to rugby this Super season with the Western Force after a 12-month stand-down by Rugby Australia following serious legal charges, of which he was cleared.
Having made his debut for Australia in 2008, Beale had said he hoped to press his selection claims for next year's series against the touring British and Irish Lions.
"I'm just super-excited to be amongst the guys again and really excited for the opportunity ahead," he said upon his Wallabies recall.
"It's been a while now but I'm ready to rip in.
"Although you'd think at the time it's a long shot, I always had a lot of self-belief."
Schmidt, who took over following Eddie Jones's disastrous World Cup campaign, will announce his matchday squad on Thursday.
Andrew Kellaway, who could feature at fullback or on the wing in the opening Test, said it was a blow to lose Beale.
"It's a massive shame seeing him go down for the mighty 'Wicks yesterday," Kellaway said on Sunday.
"We're waiting on those scans and seeing how he goes but we've got a 38-man squad here so it's very much next guy in.
"It's horrible to see but for KB, I grew up watching him and eventually playing with, someone who I now consider a close mate so it sucks to see after he was right back on the brink of where he used to be.
"We were all excited to have him back and touch wood it's not too serious but any injury sucks but especially when it's like that."
Kellaway said the Wallabies environment was very different under Schmidt after the chaotic campaign with Jones as coach.
"Attention to detail - there's a lot of good things going on," the newly-signed Waratah said of Schmidt.
"The most important thing is that we get our fundamentals right and he's been fantastic on that message.
"After you have a year like we had last year, we were pretty frustrated and disappointed with it ... it's another chance to get a win on the board and get ourselves moving in the direction we want to."
