The Nigerian-born striker limped out of the clash with Cardiff on the weekend with a recurrence of a thigh strain and is in major doubt for the Walkers Stadium fixture against the Foxes.
"Victor's is a bit of a worry because that seems to be a problem that isn't going away," said Eagles assistant Mick Jones.
Midfielder Darren Ambrose is also expected to miss tonight after sustaining a hamstring injury on Saturday.
"Darren's isn't as bad as we first thought but we're not sure if either will be ready for Leicester," Jones added.
But it was better news for Stern John who returned to action against Cardiff following an elbow dislocation he received in his Palace debut on the opening day of the season.
"He looked very good in the short time he had on the pitch," said Jones. "He looked sharp which was good news.
"To be fair I thought he might have scored with the header. And if he had a bit more match time in recent weeks I think he would have. His timing was just a bit off."