Socceroos star Jackson Irvine is set to be sidelined for the "next few months".
He hasn't played for German team St Pauli since April 12 after suffering a stress reaction in his left foot.
The club has now opted to send the 32-year-old to surgery, with the Australian to go under the knife in London on Tuesday.
Irvine has been ruled out for the remainder of the Bundesliga campaign, putting his availability for June's crucial FIFA World Cup qualifiers in serious doubt.
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"After deliberations between the medical department, club officials and the player himself, the decision was taken to treat the injury surgically," St Pauli wrote in a statement.
"The subsequent rehab procedure will take several months to complete.
"We wish Jackson all the best for the intervention and the fastest possible recovery!"
The Socceroos will host Japan on June 5 before heading to Saudi Arabia on June 11 in their last two games of the current qualification phase.
The top two-ranked teams from Group C will progress to the 2026 World Cup.
Japan hold an unassailable lead at the top of the standings, while Australia are currently in second spot and three points clear of Saudi Arabia.
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Irvine has been arguably the Socceroos' most important player in this qualifying period.
The midfielder has thrived under new coach Tony Popovic, scoring three goals across Australia's two most recent wins against Indonesia and China.