Leicester City midfielder Danny Drinkwater left Monday's match against Chelsea in the 17th minute with what appeared to be a hamstring injury.
The former Manchester United youth teamer has been one of the Foxes' standout performers this term, but manager Claudio Ranieri will have to do without Drinkwater for the rest of the tie as his side attempts to move back to the Premier League summit.
Andy King was brought on in place of the 25-year-old.
