A spring campaign is doubtful for Fontelina but trainer Anthony Cummings is counting on the sprinter's younger brother to help fill a void, starting with the Hawkesbury Guineas.

Fontelina went amiss as he was being prepared for the TJ Smith Stakes, ruling the Group Two winner out of a Singapore trip and putting further 2014 plans on hold.

"He twisted an ankle and he might miss the spring," Cummings said.

In Fontelina's sparingly raced three-year-old sibling Spy Decoder, Cummings figures the blow of losing one of his best horses for an extended time might be softened sooner rather than later.

Spy Decoder will be having the fifth run of an introductory campaign to racing on Saturday that has returned Wyong and Warwick Farm wins.

But Cummings says his last-start effort to finish fourth in the South Pacific Classic at Randwick provides an even clearer understanding of the horse's future.

"He blew the start and in a race that was leader dominated he was the only horse to make up ground," Cummings said.

And Cummings may have provided an even bigger clue to Spy Decoder's chances of measuring up to Group Three standard as he finalised stable entries for the Queensland winter carnival.

Spy Decoder has been nominated for the Doomben 10,000 and the Stradbroke Handicap.

"I think he's got a really good future and the step up to the Guineas is going to be suitable for him," he said.

Spy Decoder, a $10 chance, is drawn to receive the run of the race in the Guineas from gate three with Brenton Avdulla taking over from James McDonald.

McDonald will ride Hawkes Racing's Chautauqua, the $4.20 favourite on Friday in a reshuffled market because of the scratching of the New Zealander Beauty's Beast.

He will also ride Leebaz for the Hawkes stable in the Hawkesbury Gold Cup with the four-year-old the shortest-priced runner at the meeting after firming from $2 to $1.75.

Reported to have knocked back a ride for Qatar Racing in the 1000 Guineas at Newmarket in England at the weekend, McDonald also has the mount on Darley Crown second favourite Cosmic Endeavour.