One of the world’s best players, Kerr’s absence is a huge blow to the Matildas who played the Republic of Ireland in their opening World Cup game on Thursday.
“Unfortunately, I sustained a calf injury yesterday in training,” Kerr wrote on Instagram.
“I wanted to share this with everyone so there is no distraction from us doing what we came here to achieve.”
According to the Matildas, Chelsea forward Kerr will also miss next Thursday’s match against Nigeria, but should return for the July 31 game against Canada.
Kerr has been a key player for Australia throughout her international career, scoring 63 goals in 120 appearances for her country.
Kerr racked up five goals in four matches at the 2019 World Cup, including four goals against Jamaica in the group stage.
The 2023 edition represents her fourth World Cup, having debuted at the showpiece event in Germany in 2011 as a 17-year-old.
The 29-year-old Kerr has been equally pivotal in her club Chelsea’s success in recent seasons, picking up the Player of the Year award in England’s Women’s Super League in both of the last two seasons as the side won league and cup doubles.
Manchester City striker Mary Fowler, who scored the winner in a friendly against France last week, started in Kerr’s place.
The 20-year-old Fowler, wearing the number 11 shirt, started brightly alongside Arsenal’s Caitlin Foord as Australia dominated the opening exchanges against the Republic of Ireland.
Thursday’s match marks a first World Cup outing for Fowler, who in 2019 traveled to France with the squad at the age of 16 but didn’t play at the tournament. She burst onto the international scene aged just 15.
Even without its captain, Australia should still have enough quality to progress from the group stages.
Additional reporting by Angus Watson.