Promising youngster Invisible is out of the Golden Slipper after suffering a bone fracture during his unplaced run in the Magic Millions Classic.

Co-trainer Michael Hawkes confirmed the colt would miss the autumn carnival in Sydney after x-rays revealed he had fractured a splint bone.

It was unclear at what stage of Saturday's race Invisible suffered the injury but Hawkes said the horse was noticeably sore when he returned to the race day stalls at the Gold Coast.

"It was severe enough that when he got back to the stalls he was lame," he said.

"We x-rayed him on Sunday morning when we found the crack had presented itself.

"He will be out for nine months."

An impressive winner on debut at Canterbury in December, Invisible was heavily backed in pre-post betting for the Magic Millions Classic.

In spite of the injury he suffered in the run, he still hit the line strongly to finish eighth to Unencumbered, beaten less than five lengths.

Hawkes said the stable was gutted by the colt's injury as they had expected him to be hard to beat in the $3.5 million race.