A statement from Arsenal on Tuesday said: “We can confirm that Beth Mead suffered a ruptured anterior cruciate ligament in our match against Manchester United at Emirates Stadium on Saturday.
“Unfortunately, this means that Beth is set for an extended period on the sidelines. She will see a surgeon in the coming days, after which further details on timescales will be established.
“Everyone at the club will now be supporting Beth and working hard to get her back on the pitch as soon as possible.”
Mead has scored three goals in the WSL and two in the Champions League for the Gunners this season, which follows her starring role in England’s triumph at the Euros during the summer.
She was named player of the tournament and claimed the Golden Boot with six goals, and last month was Ballon d’Or runner-up behind Spain’s Alexia Putellas.
England will be back in major tournament action next summer at the World Cup taking place in Australia and New Zealand, from July 20.