Darley's Blue Diamond Stakes outsider Mohave is receiving treatment for a throat complaint.
A routine scope following the colt's trackwork gallop on Tuesday found mucous in the two-year-old's throat.
Stable foreman Paul Snowden told Racing Victoria stewards Mohave has been put on a course of antibiotics.
Mohave burst into Blue Diamond prominence with a Preview win last month but the chestnut has fallen from favour since finishing down the course in a Prelude behind Rubick.
In spite of drawing gate six, Mohave is out to $35 to win Saturday's $1 million race with stablemate Earthquake ($3.40) one of the favourites.