The centre back has not played since November’s win over Newport and will miss Tuesday’s game against Fulham, which falls on his 35th birthday, and at least four more matches, including the Carabao Cup quarter-final against Newcastle, with a calf injury.
Manager Brendan Rodgers said: “Jonny will be until February. It looks like it will be longer than we thought so probably early February.”
It leaves Rodgers short of fit defenders, with Ricardo Pereira, James Justin and Ryan Bertrand also out.
Meanwhile, striker Patson Daka went off after a quarter of an hour in Friday’s defeat by Liverpool with a hamstring problem, and he is set to sit out the Fulham game.
Top scorer James Maddison has seen a specialist about the knee problem that means he has not played since before the World Cup. He will not figure against Fulham or in Saturday’s FA Cup tie against Gillingham but might be able to come back into contention after that.
Rodgers added: “Hopefully we will get no reaction and can then rejoin the training group.”