Shadow Hero is the new favourite to add the Randwick Guineas to his Group One Spring Champion Stakes with the scratching of Super Seth.

The Anthony Freedman stable told stewards Super Seth had an elevated temperature and abnormal blood picture on Wednesday.

The colt had been the dominant $2.70 favourite but the market has now opened up with the Mark Newnham-trained Shadow Hero at $4. 60 ahead of Castelvecchio at $5.50.

Freedman bypassed last Saturday's Australian Guineas won by Alligator Blood in favour of Saturday's Randwick Guineas.

Super Seth inflicted the only defeat on Alligator Blood so far when he beat him in the Caulfield Guineas in the spring.

This preparation he has won the Group Three Manfred Stakes and run second to Streets Of Avalon in the weight-for-age Futurity.

New Zealand's Waikato Stud has bought a controlling share in Super Seth but has given no indication when he will be retired from racing.

The Freedman-trained Victoria Derby winner Warning is an $11 Guineas chance.

Expressway Stakes winner Standout is the $2.60 favourite for the Group One Canterbury Stakes but the colt's trainer Gerald Ryan admits he will have a decision to make if the track is heavy.

The three-year-old, a brother to 2013 Golden Slipper winner Overreach, Standout has won four and run second at the other of his five starts which have all been on good ground.