But United boss Ferguson is upbeat about the prospects of the French defender figuring for the club again in the current campaign.
"I'm sure Mikael will be back in March," Ferguson told Manchester United Radio.
"We had him operated on in France last week and it all went well.
"It was pleasing to see there was no further damage other than the cruciate ligament. That's a big bonus because sometimes there can be cartilage problems that also come along."