Claude Puel has confirmed Marc Albrighton needs surgery on a hamstring injury and may not return until the end of the season.
The winger signed a new contract last month but may not be able to add to his 22 league appearances in 2018-19.
Albrighton missed last weekend's loss to Manchester United and Puel revealed the 29-year-old will be a long-term absentee.
"We now know [more about] the injury to Marc," he told reporters ahead of Sunday's visit to Wembley to take on Tottenham.
"He's had a serious hamstring injury. It's bad news for us, for the team, and I think he will not be available until the end of the season.
"Marc gives the team spirit and aggressiveness. We will have to find another balance in the team so we will see.
"It's a bad thing for him and for us but it will be an opportunity for another player to show his quality and we'll have to manage this situation. He will have surgery."
At the end of Leicester's defeat to United, Puel and striker Jamie Vardy appeared to be involved in a confrontation.
But Puel said the former England international was merely annoyed after his side were beaten at Old Trafford.
"I have a good relationship with him," Puel added. "We know Jamie and after he has lost, he is never happy and that is normal for a player.
"If I thought one of my players was disrespectful, to me or to the club, there would be a sanction. That is not the case with Jamie."
Loan signing Youri Tielemans could make his Foxes debut at Wembley after being passed fit.
"I haven't taken my decision for the next game," Puel added. "He has worked hard in training and we'll see if he can bring his qualities."
