Ritchie said he had made his way to Melbourne as Mahrajaan was now essentially weighted out of two-mile races in his adopted homeland.
"We have no idea if he's good enough for a Lexus Melbourne Cup, but he's 23rd in order now, so he's going to have a go," Ritchie said.
"But we won't be running if he can't perform in his two lead up races.
"He runs on Saturday and then probably in the Moonee Valley Cup which is 10 days before the Melbourne Cup which should be ideal.
"I think running him in anything less than 2500 metres he wouldn't be competitive as it is still 700 metres short of what his best trip is."
Mahrajaan has been to Australia once previously, finishing last in the Sydney Cup (3200m) in April, a campaign Ritchie said was a disaster.
The Randwick track was flooded the week before the Sydney Cup and while the track had improved, it was not the gelding's ideal surface.
But Ritchie also blamed himself.
"We were trying to peak him for a third time in one season for a two-mile race," Ritchie said.
"He was tough enough to do it twice, but I should have been smarter than that. It was a bridge too far, even if it was a good track.
"He was a pretty tired horse when he came home.
"He had a good break and we're trying to peak him for the Lexus Melbourne Cup.
"We don't have any illusions of grandeur, but if we can get some money, we would be happy."
Ritchie is preparing Mahrajaan from the Warrnambool stables of Matt Williams, the yard he stayed with when he campaigned Nassak Diamond to win the Jericho Cup last December.
He said the benefit of Williams' stable is a paddock, the same size Mahrajaan lives in back home in New Zealand.
"While it would have been better for us, if we had taken him to Flemington, I'm sure we would start to lose him mentally within two weeks," Ritchie said.
"So, I think he's in the ideal place.
"He was born in the US, went to Dubai to be broken in, raced in England, came to Melbourne for quarantine for New Zealand, then was on a plane to Christchurch and floated up to Auckland, has flown over to Sydney and back, so the three hours travelling on a float from Warrnambool to Flemington on race day is not going to worry him.
"He looks fantastic and will present in superb order on Saturday."