Australia captain Sam Kerr out of Women's World Cup opener and Nigeria clash

The Chelsea striker is Australia's all-time goalscorer of either gender with 63 goals across 121 caps, but she will be forced to watch Thursday™s opener against the Republic of Ireland from the bench after sustaining the injury during a training session on Wednesday.

Australia next face Nigeria on July 27 and will hope Kerr is fit enough to start their final group stage match on July 31 against Olympic champions Canada, the highest FIFA-ranked Group B nation.

A Matildas tweet read: "Sam Kerr is unavailable tonight after she picked up a calf injury at training on MD-1.

"Sam will be unavailable for the next two matches, with the Matildas medical team to reassess her following our second group-stage match."

Football Writers' Association women's footballer of the year Kerr, 29, took to Instagram to express her disappointment in a post that read: "Unfortunately I sustained a calf injury yesterday in training.

"I wanted to share this with everyone so there is no distraction from us doing what we came here to achieve.

"Of course I would have loved to have been out there tonight but I can't wait to be a part of this amazing journey which starts now."