Parling, who toured with England last summer after playing a major role in Tigers’ successful defence of the Premiership title, was injured just minutes into the Aviva Premiership fixture against Quins after appearing as a second-half replacement.
“Geoff’s had a scan and there is significant damage in that knee,” said Tigers director of rugby Richard Cockerill.
“He will have surgery in the next few days and his season is finished. It’s horrendous for him first and foremost, and really bad news for us because we thought we were getting him back after his injury last summer and that would bolster our second-row options.
“Geoff is a quality player and it’s a crying shame for us as a club and obviously for him as an individual.”
Tigers have suffered a further blow with the news that back-rower Ben Pienaar has suffered an Achilles injury.
“We’ve had such bad luck with injuries with Jeremy Staunton, Boris Stankovich, Ben Woods, Richard Blaze, Geoff and now Ben who has ruptured his Achilles,” added Cockerill.
“You have a look at what you do, but it all comes down to bad luck and you hope at some stage that it is going to change.”