Joe Didulica is unsure when he will be able to return to action after revealing he is still being troubled by the after-effects of the injury he picked up against PSV Eindhoven.
The Australian keeper suffered severe concussion against PSV in October and is still not 100 per cent.
Didulica claims he suffers bouts of nausea when put under strain and is unsure if he will play again this term.
"Every time I train, I throw up," he told Algemeen Dagblad.
"It's difficult to predict when I will be fit again."
AZ are also set to be without David Mendes da Silva for the next six weeks after he picked up a knee ligament injury.