The 28-year-old is due to have an operation on his foot on Friday after suffering the injury on Thursday morning in a huge blow to the Foxes' survival hopes.
Ben Hamer is set to deputise - starting against Manchester City on Saturday - after boss Nigel Pearson announced the news.
He said: "It's very unfortunate, clearly the lad is distressed about it and he will be a miss for us but, again, you have to deal with it
We can't change it.
"I've got an idea (of how long he will be out), the best thing to do is update you on Saturday
Hopefully he'll have the operation on Friday and an optimistic view would be four to six weeks but it could be longer, we don't know.
"It will depend on what the surgeon finds when he deals with the situation.
"There was no contact, it's just foot to the floor, I didn't see a twist and these things happen."
Schmeichel has been one of the Foxes' outstanding performers, despite them sitting bottom of the Barclays Premier League.
They host champions City on Saturday but Ritchie de Laet is available after illness while Matt Upson will not feature despite nearing a return from a foot injury.
Source : PA
Source: PA