All-Star Mile hopeful Catalyst has been sent to the Ballarat Vet Clinic to determine the extent of a back issue.

After initially believing Catalyst had pulled up well from his unplaced run in Saturday’s Group One Australian Guineas at Flemington, trainer Clayton Chipperfield told Racing Victoria stewards on Tuesday the gelding had been sent to the vet clinic for “diagnosis of a back area issue”.

Catalyst has a spot in Saturday week’s $5 million All-Star Mile at Caulfield.

The Group One NZ 2000 Guineas winner finished a close second to Alligator Blood in a thrilling Group Three C S Hayes Stakes (1400m) at Flemington last month before his sixth in the Australian Guineas.

Chipperfield said after the Guineas the intention was to press on to the All-Star Mile with blinkers to be re-applied.

Should Catalyst not be fit to take his place in the All-Star Mile on Saturday week, his spot would be offered to the first emergency.

Alizee heads the list of provisional emergencies.

Alligator Blood dominates the All-Star Mile market at $2.80 with Catalyst easing to $15.