It's a bitter blow for Fitzgerald who had forced his way back into the Leinster first team after injury ruled him out of the RBS 6 Nations, while he has also endured a lengthy knee injury which caused him to miss the entire 2010 Six Nations campaign.
Leinster confirmed in a statement that they consulted with the Irish RFU medical staff before deciding that Fitzgerald would undergo surgery, and head coach Joe Schmidt has tipped the flyer to make a full recovery.
"Obviously to lose a player of Luke's pedigree at such a crucial time of the season is a massive blow, not just for the team and our supporters, but also for the player himself," said Schmidt.
"Luke has been in fine form recently and as well as his capabilities on the field, he is a positive and popular presence within the dressing-room.
"Knowing Luke, he will be determined to overcome this setback and aggressively tackle his rehab to regain full fitness and he will continue to benefit from the full support of Leinster Rugby and the IRFU during that timeframe."