Following subsequent assessments from the Welsh region's medical team Allen will go under the knife next week before beginning a three-month rehabilitation period.
Allen had made four GUINNESS PRO12 appearances this season, crossing in the New Year's Day win over Scarlets, having already suffered a hamstring tear at the Rugby World Cup this season.
A statement on the Cardiff Blues official website read: "Allen, 23, has seen specialists this week and following that consultation, and in conjunction with the medical teams at the WRU and Cardiff Blues, he will now undergo surgery next week.
"The centre will commence a three-month period of rehabilitation following his operation and Cardiff Blues will make relevant future announcements.
"Everyone at Cardiff Blues wishes Cory the best with his rehabilitation and we look forward to seeing him back in action next season."
To buy tickets for the GUINNESS PRO12 Grand Final click here. Also follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12.
63x46.png){kind=logo}