The 24-year-old was initially given good news after he was discharged from hospital but further investigations into the injury have revealed more extensive damage. As a result, Lowe won't feature again at all this term.
"Following further scans and guidance from specialists over the past four weeks, George has been advised not to play again this season," read a statement on the Harlequins website.
"Instead he will undertake a programme of treatment that aims to have him fit to return to action for the 2014/15 season."
Fears that Lowe would be sidelined for longer than expected prompted Quins to sign Gloucester centre Tim Molenaar earlier this week but it will be hard not to feel Lowe's absence given his standing at the club.
A product of the Harlequins Academy, Lowe made his first-team debut in 2009 and has 17 European appearances and an Amlin Challenge Cup winners' medal to his name.
He has worn Quins senior colours on more than 100 occasions and was part of England's tour to South Africa in 2012.
The news that he will be unavailable until the summer comes after Quins suffered back-to-back losses at the start of their current Heineken Cup campaign.
Conor O'Shea's men were beaten 33-26 at home by the Scarlets and 23-16 at ASM Clermont Auvergne, leaving themselves with an uphill struggle to reach the last eight for the second year running.