Wilfred Ndidi on Saturday had a surgery on a thigh injury that Leicester expect to keep him sidelined for 12 weeks.
The Nigerian sustained the injury during the second half of the Foxes’ 4-2 win over Burnley last Sunday, but still completed the match.
It is a huge blow for Leicester, as Ndidi is one of the best defensive midfielders in the country and has been impressing in central defence in the absence of the suspended Jonny Evans.
‘It’s an abductor problem and it’s unfortunate, the muscle has come right off the bone,’ said Leicester boss Brendan Rodgers.
‘He will be out for up to 12 weeks, we think.
‘He felt some pain and there is no doubt he will be a miss for us.
‘I’m sure he’ll make a really good recovery and we’ll welcome him back when he comes back.’
Nampalys Mendy will continue in the holding midfield role when Leicester take on Manchester City on Sunday, although Ndidi’s absence is unlikely to change Rodgers’ transfer plans as he continues to press for a new centre-back.