Manchester City forward Mary Fowler has ruptured her anterior cruciate ligament.
The Australia international suffered the injury to her right knee during City's FA Cup semi-final loss to Manchester United last weekend, with scans confirming the severity.
Fowler is now set for a number of months on the sidelines, with a statement from City reading: "Mary will remain under the care of the club's medical team and start her rehabilitation. Everyone at City wishes Mary all the best on a full and speedy recovery."
The 22-year-old had been in good form for City, scoring six goals in the Women's Super League and leading the table with seven assists.
Last summer she shone at the World Cup, impessing against the Republic of Ireland in the group stages and helping the Matildas to reach the semi-finals, where they were beaten 3-1 by England. Fowler's father is from Dublin.
She said: "I'm really disappointed to be facing some time out of the game. It's never easy when something like this happens, especially when you've been working so hard and feeling good. The road ahead will be challenging, but I'm ready to take it on.
"There's still so much I want to achieve and I'll be using this time to grow in every way I can. I'm committed to doing the work, staying positive and coming back better than ever."
Matildas interim head coach Tom Sermanni said: "This is tough news for Mary and for all of us who know the dedication and passion she brings to her craft.
"She's an exceptional talent and a much-loved member of our team, and we know she'll meet this challenge with the same courage she brings to the pitch."
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