West Ham have been dealt an injury blow after manager David Moyes revealed Felipe Anderson will be sidelined for a month.
Anderson, 26, missed last weekend's draw at Everton after falling awkwardly in the Hammers' 1-0 defeat against Sheffield United earlier this month.
And speaking ahead of his side's midweek trip to Leicester, Moyes revealed the Brazilian, who opened his account for the season in the Scot's first game back in charge against Bournemouth on New Year's Day, is set to be absent for longer than first expected.
Andriy Yarmolenko has also been ruled out until February. But the Hammers could be boosted by the return of Michail Antonio, who has been missing since December with a hamstring issue.
"Felipe's got a problem with his back, which looks like it's going to keep him out for about four weeks," said Moyes.
"Michail Antonio is getting closer to fitness but Yarmolenko is the best part of three weeks away. We could do with getting them back."
West Ham will head to the King Power Stadium looking over their shoulder after taking just one victory from their previous five Premier League outings.
Indeed, the Hammers sit just one point above the drop zone as they fight to secure their top-flight status following Manuel Pellegrini's dismissal.
Moyes has taken four points from his opening three matches since he returned to the struggling east London club.
"We're trying hard to do so," said the West Ham boss, when asked if his team is taking a step in the right direction. "We're trying to get some wins, and not just on the pitch.
"We've defended better in recent weeks. We've started very well. We want to keep scoring goals and we also need to make sure we're not giving the team opportunities to score.
"I've really enjoyed my period coming back. It's been busy. It's still busy but the biggest thing is that the players have been brilliant.
"They've given me 100 per cent in every game. I can only praise them for it. They've knuckled down and they've done a great job."