Trainer David Hayes today revealed that Kibbutz had pulled up lame in the off fore leg after a track gallop at Flemington last Saturday.
Hayes advised stewards that Kibbutz has since been treated for a foot abscess and had not missed any work since Saturday.
However he is monitoring the horse's condition and has been told stewards will order an official veterinary examination of the four-year-old before Saturday's 8am scratching deadline.
Kiwi stayer Nom Du jeu has also been under a fitness cloud after a report that he had suffered from travel sickness after arriving in Melbourne last weekend.
Racing Victoria vet Dr P O'Callaghan today spoke with the veterinary surgeon supervising Nom De Jeu and established that the AJC Derby received an EI vaccination last Sunday.
Blood sample were taken from Nom Du Jeu on Monday and the results have indicated a slight elevation of his white blood cells and an increase in his protein levels which indicates signs of inflammation.
Dr O'Callaghan reported that the results could be attributed to some form of travel sickness and also a possible reaction to the EI vaccination.
Dr O'Callaghan has requested the results of previous blood counts taken from the horse in New Zealand to use as a comparison with a blood count that was being taken today.
Nom Du Jeu has galloped since his arrival and today was reported to be bright and alert.