General manager Pierre Gauthier announced to reporters Saturday that the star defenseman will need arthroscopic surgery on his knee after further tests this week revealed swelling in the surgically repaired knee.
Gauthier called it a simple procedure to clean up debris and possible scar tissue in the knee.
"The prognosis that we're hearing is three weeks or so," Gauthier said. "It could be longer depending on what they find in there."
The Canadiens had hoped that Markov could return on Montreal's current three-game West Coast trip, but Markov felt discomfort as his return neared and sought a medical check-up a few days ago.
Markov hasn't played since November 2010 after struggling to return from a second operation on his ACL last December.