Lyon women's star Hegerberg out for months with knee ligament injury
"A date for surgery will be fixed in the coming days," the club said in a statement.
Hegerberg, 24, said the injury to the Anterior Cruciate Ligament (ACL) in her right knee was a setback but promised to return "soon."
"I ruptured my ACL this weekend. This is a setback for me, but I'm going to work through this with all my heart and my energy," she tweeted.
"The best is yet to come. YOU'LL SEE ME SOON!"
Hegerberg, who chose not to play for Norway in the 2019 World Cup, has scored 38 goals in 66 appearances for her country.
Lyon, European champions for the last four seasons, face Bayern Munich in the quarter-finals on March 25 and April 1.
Hegerberg is top scorer in the competition with 53 goals in 50 matches.
Lyon has also been without France defender Griedge Mbock Bathy and French attacking star Eugenie Le Sommer, who are both injured, in recent weeks.