Johann Berg Gudmundsson faces another lengthy spell on the sidelines after sustaining a 'reasonably serious' hamstring injury while on international duty.
The winger, who will celebrate his 29th birthday later in the month, hobbled off in the early stages of Iceland's defeat to world champions France.
The former Charlton Athletic man was replaced by Jón Daði Böðvarsson in the Euro 2020 Group H qualifier at Laugardalsvöllur in Reykjavík and Burnley boss Sean Dyche confirmed the news.
He said: "Johann Berg Gudmundsson won't be figuring [against Leicester City], he unfortunately got injured on international duty.
"It's a reasonably serious hamstring injury so it won't be days, it will be more like weeks, but I don't know how many yet, but it is serious enough to speak of in that way."
It's another significant setback for the one-time AZ Alkmaar man, who only made 19 starts last season due to injury.
Meanwhile, Danny Drinkwater, who won the Premier League title with the Foxes, won't be fit in time to face his former club at the King Power Stadium.
Midfielder Jack Cork has a 50/50 chance and leading scorer Ashley Barnes will face a late fitness test. Erik Pieters, however, is available for selection again after limping off in the win over Everton at Turf Moor.
"Drinky is not ready, he is making progress but he is still not quite there," said Dyche. "Corky is touch and go with a shoulder blade injury which has a fraucture.
"Ashley Barnes has a tight groin so we will have to make a judgement call on those two. It is a judgement call on the risk and reward of playing. Erik should be fine, he has trained all week so he is clear."