Manchester City striker Fowler started Australia's opening win over the Republic of Ireland, which captain Sam Kerr missed with a calf injury.

Kerr remains out for the Nigeria match.

Australia face the African side in Brisbane on 27 July knowing a win would guarantee them progression from Group B into the round of 16, following their 1-0 victory over the Irish at Stadium Australia.

But the absence of Fowler - who was expected to line-up alongside Caitlin Foord up front for the Matildas, as she did against the Republic - leaves Australia short on attacking options.

Emily van Egmond and Alex Chidiac are among the players in contention to replace Fowler, while Everton forward Clare Wheeler is also an option.

"Forward Mary Fowler and defender Aivi Luik will be unavailable for Thursday night's clash with Nigeria with both players having been ruled out after sustaining mild concussions in separate incidents at training on Tuesday," a statement

from the Australian FA read.

They also confirmed both players have recovered, but will not play against Nigeria due to Football Australia's concussion protocol.

Fowler, 20, and Luik, 38, could both be available to face Canada in Australia's final Group B clash on Monday.