The Brazilian attacker was withdrawn from Sunday’s 0-0 draw at Arsenal and taken straight to hospital with possible concussion after a heavy collision with goalkeeper David Ospina.
Mourinho told Sky Sports after the game that they had been ‘scared’ for the 23-year-old and he would undergo a series of scans.
But the Blues boss confirmed on Monday: “Oscar left the hospital and stayed at home last night. He should be here today. Everybody will travel to Leicester”
Mourinho could not confirm whether striker Diego Costa would be fit to return at the King Power Stadium on Wednesday night however.
Costa, 26, has missed the last three matches against QPR, Manchester United and Arsenal with a recurring hamstring problem.
Chelsea face a Leicester side on an upsurge in form, having lifted themselves out of the bottom-three for the first since November with a fourth straight victory on Saturday.
And Mourinho has admitted his options remain limited if Costa is not fit, insisting he will not call on the club’s youth players, who contest the second leg of their FA Youth Cup final against Manchester City, which they lead 3-1, on Monday night.