Matildas captain Steph Catley appears in doubt for Australia's Olympics opener against Germany as she battles a lower leg injury.
Catley and versatile defender Kaitlyn Torpey have both been ruled out of Sunday's friendly against Canada in Marbella, Spain with lower leg injuries.
While Torpey appears further along and likely to feature against Germany, coach Tony Gustavsson said it was "too early to say" if Catley would be available to face Germany in Marseille on July 25 (local time).
Australia then play Zambia in Nice on July 28 then the US in Marseille on July 31.
Catley is skipper in Sam Kerr's absence and stood in with aplomb when a calf injury sidelined the Chelsea striker early in last year's Women's World Cup.
She would be sorely missed for both her leadership and quality at left-back if unavailable.
Gustavsson refused to give any details or specifics on Arsenal star Catley's injury.
"It's a lower leg injury that the (medical staff) need to make sure that they treat right and don't want to risk anything," Gustavsson said.
"I wish I could (provide more details) but I want to respect Steph, her club and the environment outside here.
"Always when something happens outside of our environment, it's not our responsibility to communicate it.
"The only thing I can say is that she's here now, she has a lower leg injury and we're doing everything to get her back."
There is some relief, at least, via a late tweaking of Olympic squad rules.
Teams will now be able to use their four alternate players during the tournament to temporarily replace any of their 18 squad members for injury, illness, or mental health reasons - provided they give six hours' notice before a game.
The injured player can rotate back into the squad again when available, rather than being sidelined for the rest of the tournament.
"It's a great change, considering player welfare and the load for the players over these last couple of years," Gustavsson said.
"It's massive."
Tottenham defender Charli Grant and Leicester left-back Courtney Nevin are obvious replacement options, with goalkeeper Lydia Williams and attacker Sharn Freier the other two alternates.
Gustavsson insisted even if the rules hadn't been tweaked, he never would have left Catley out of the squad.
"Let's say in a few days from now that I get the decision that she won't be available for the 25th - even if there wasn't a rule change I would have kept her," he said.
"It's Steph Catley, it's our captain and if we have her available for the second game or third game, I would have kept her – that's how important she is to this team."
