Scotland midfielder Kim Little has ruptured her anterior cruciate ligament injury, meaning she is almost certain to miss Euro 2017.
The 26-year-old, who has more than 100 senior caps, sustained the injury in training with her club Arsenal.
"Our medical team will be working hard to ensure the Scotland international returns back to full fitness as soon as possible," the club said.
"Everyone at Arsenal would like to wish Kim the best with her recovery."
Scotland women, who will feature at their first major finals, will play England (19 July), Portugal (23 July) and Spain (27 July) in the Netherlands.