The 34-year old central defender sustained the injury in an awkward fall in last night's 2-0 Champions League win at Benfica and will now undergo the appropriate treatment before he looks to return in early December.
"The club captain will undergo conservative treatment and is expected to be out for about eight weeks," read a Barcelona statement.
Manager Tito Vilanova admitted that Puyol's injury has the Catalan giants stretched in the central defensive position especially with Gerard Pique out with a foot problem.
"I've always said it, we've always had problems with our central defenders, but we'll move forward," he said.
"It's not just that we've lost Puyol for the Clasico on Sunday, but we've lost him for other matches as well.
"The injuries mean we will have to play players in positions that aren't their own, but we'll use our youth players, that's why we have them."