Jackson Irvine has been ruled out for St Pauli. (Getty Images: Pau Barrena)
In short:
Socceroos midfielder Jackson Irvine will be out of action "until further notice," says his club side, St Pauli.
Irvine has had a recurrence of a foot injury that sidelined him for almost six months last year.
What's next?
The FIFA World Cup gets underway in the USA, Canada and Mexico on June 11.
Jackson Irvine has joined Socceroos coach Tony Popovic's growing injury list after the influential midfielder's club ruled him out of action indefinitely.
Irvine's Bundesliga club, St Pauli, said on Wednesday the 32-year-old would be unavailable "until further notice", in an announcement that is sure to cause Popovic concern just five months out from the World Cup.
The 80-cap midfielder has suffered a recurrence of the stress injury in his left foot that ruled him out of last year's World Cup qualifiers, and led to the St Pauli captain spending the best part of six months on the sidelines.
It is unclear whether Irvine, who underwent surgery last year, will have to go under the knife again, but his absence is a major blow for St Pauli as it battles to avoid relegation.
"The next steps are now being discussed by all the parties involved," St Pauli said in a statement.
The midfielder had just returned to full fitness over the past month, playing five straight games for St Pauli in the Bundesliga and German Cup.
Irvine has often acted as the Socceroos' back-up captain to Mat Ryan during Popovic's reign.
His latest injury setback will also be a worry for the Socceroos set-up as the World Cup in the US comes into focus.