The Royals are counting the cost of their midweek Carling Cup defeat to Northampton.
Left-back Marcus Williams, midfielder Jem Karacan and winger Michail Antonio all picked up knocks against the Cobblers, with Antonio having to be replaced at the break.
All three are doubtful to face the Foxes at the Walkers Stadium, while right-back Julian Kelly is definitely out after pulling his hamstring against Ian Sampson's side. First-choice Andy Griffin is still struggling with a hamstring injury of his own so midfielder Brynjar Gunnarsson may have to fill in.
Midfielder Jay Tabb is out after he had ankle surgery this week and is joined on the treatment table by club captain Ivar Ingimarsson (hamstring) and Chris Armstrong (knee).
Kick-off is at 5.20pm.