"We had a bug through the team during the week but we thought they were over it," said Purdon.
"They had good blood reports and we even had Laz scoped on the morning of the race so we could keep the stewards up to date but clearly he was still below his best.
"So while I was disappointed in him because he tried so hard, it was hardly ideal."
Purdon said Lazarus appeared to come through the hard run behind long-time rival Tiger Tara well and looked fresh yesterday, and he expects to know more about his well-being after fast work on Tuesday.
But that isn't the only problem facing Lazarus as he drew the outside of the front line at yesterday's barrier draw, meaning he will start from barrier eight. Since the Miracle Mile moved to Menangle a decade ago no horse has even placed in the race from barrier eight.
That saw him move from $1.70 on Saturday morning to $2.20 with the NZ TAB last night but he could stretch out to $3 with some bookies before race start time, especially depending on how Purdon assesses his bounce back to peak fitness.
The big winner in the draw was the faster of Saturday's two prelude winners in Anything For Love, who has barrier three for the Mile while Tiger Tara's unbelievable run of ace barrier draws continued.
He has now drawn the ace in the Inter Dominion Final, Hunter Cup and Miracle Mile and whether he can hold Anything For Love at the start will be a crucial factor in the race.
A$750k Miracle Mile
The field for the A$750,000 Ainsworth Miracle Mile at Menangle on Saturday night is:
1: Tiger Tara (1)
2: Atomic Red (2)
3: Anything For Love (3)
4: My Field Marshal (4)
5: Jilliby Kung Fu (5)
6: Soho Tribeca (6)
7: Lennytheshark (7)
8: Charlaval (8)
9: Let It Ride (9)
10: Lazarus (10)
Emergencies: Let It Ride, Atomic Red.