Less than 24 hours after establishing himself as Gai Waterhouse's leading Golden Slipper hope, Fighting Sun has been ruled out of the autumn with injury.

The colt was a dominant winner of Saturday's Canonbury Stakes at Rosehill and immediately elevated to second favouritism for the $3.5 million Slipper on April 5.

But he was found to be sore on Sunday morning and taken to the Randwick Equine Centre for scans.

Earthquake heads the Golden Slipper market at $4.60 but a decision on whether she runs will not be made until after Saturday's Blue Diamond Stakes at Caulfield for which she is also favourite.

Magic Millions winner Unencumbered is the $8 second elect for the Slipper with Fighting Sun's stablemate Nayeli at $11 alongside Rubick.

Both Nayeli and the Gerald Ryan-trained Rubick also run in the Blue Diamond.