Rotherham United hot-shot Freddie Ladapo winning battle for derby fitness
However, he returned to training this morning and will be in the squad this weekend unless he suffers a reaction.
"He trained today and trained quite well," manager Paul Warne. "He was a bit 'blowy'.
"We'll just see how he reacts tonight really. We will see how he comes in tomorrow morning and we will make an informed decision then.
"He will definitely a play a part but how much of a part we will have to see.
"He had tonsillitis. He has taken penicillin and it has calmed down."
Centre-half Angus MacDonald, out with an unspecified condition, and back-up goalkeeper Josh Vickers, who has a groin problem, are the only Rotherham absentees.
Central defender Curtis Tilt is back with the main group after a hamstring pull but the Owls clash will come too soon for him.
The match, which pits two top-six League One sides against each other, is heading towards a sell-out and less than 300 tickets remained for sale at the close of business last night.
Ladapo is desperate to feature after his stunning 97th-minute strike in S6 last term that secured a 2-1 victory for the ten-man Millers.
Warne said: "He caught me looking at him in training a couple of times when he was blowing a bit and immediately tried to pretend he was all right!"