"And we even had a vet scope him this morning (Saturday) and said he was fine to race.
"We told the stewards all about this and I still thought he would win but once he got crossed at the start and had to work hard it showed he wasn't at his best."
Purdon said the type of bug which must have been lingering in Lazarus's system tends to clear up quickly and he is hopeful he can have him back to his peak for next Saturday.
"But it knocks your confidence. I will know a lot more on Wednesday or Thursday." My Field Marshal gives New Zealand two pacers in the eight-strong field but with Lazarus best known for his epic wins over longer distances, he rivals will feel it is game on for next Saturday night.
The all-important barrier draw for the Miracle Mile will be held around 3.30pm Sunday afternoon NZ time.
The field for the race is: Anything For Love, Soho Tribeca, Charlaval, Tiger Tara, My Field Marshal, Lazarus, Lennytheshark, Jilliby Kung Fu. Emergencies: Let It Ride, Atomic Red.