But Elmo and Isaacson will start in the Norwood Gold Cup on Wednesday afternoon, unless something goes wrong.
Isaacson has also entered Elmo in the 7-year-old, 1.25m class on the Wednesday morning, to give the young horse a chance to see the arena.
"If you are going to enter in those bigger classes he has to jump well, so I'll see how he goes in the Norwood before I decide if I'll take him any further," Isaacson said.
"It doesn't seem to phase him to tackle bigger fences, he's got the confidence. But if they get the speed wobbles, which he doesn't, you've got to be careful. You've got to think of your horse's legs when you are facing the big jumps."
And the veteran showjumper admits there's pressure on him too.
"I need to have both eyes completely on the job," he said. "Tackling those bigger fences, well, horses can't sort everything for you. You have to do something yourself. Horses can't dig you out of a hole."
Isaacson doesn't go to the gym and admits he's got the odd tweak and twinge at times.
"You've got to be riding fit," he said. "It's like a lot of things, compare me to Dannevirke's Maurice Beatson who is jumping a lot more horses and entering more showjumping events - it's easier for him."
Isaacson will also have his other smaller 7-year-old My Art Work at Horse of the Year, jumping in the lesser classes.