While the top Sydney trainer thought he was an outside chance of winning back-to-back Black Opals with this year's runner Sidestep, he was hopeful of catching star stayer Niwot off guard to win this year's Canberra Centenary Cup at Thoroughbred Park on Sunday as well.

Snowden claimed the 2012 Opal when Epaulette stormed home to salute. Sidestep will be his only runner this time, following the scratching of Aspen, who drew barrier 20. Following Epaulette's win, he backed the Black Opal as an ideal lead-up run for the $3.5 million Golden Slipper - the world's richest race for two-year-olds.

While he thinks the timing of the race will stop it from attracting the best juvenile horses in the land, he does think it's strong enough to reclaim the group 3 status it lost in 2006.

The $250,000 Black Opal is currently a listed race - the level below group 3.

''It's definitely [a group 3 race] … you're probably not going to get the A-grade horse because the three lead-up races going into the Slipper are here at Rosehill, so they're always going to take a bit of the shine off it,'' he said.

''As far as class goes, and the horses that have won it and are likely to win it over the next couple of years, it definitely deserves that kind of status.

''And the prizemoney is very good, it's very good for two-year-olds at this part of the season.''

With the non-acceptance of All The Talk, Snowden said the David Payne-trained Criterion was the class horse of the field, but his wide barrier (18) made it an open race.

He said Sidestep deserved a crack at this class of race, but he admitted he wasn't as advanced in his preparation as last year's winner - having had only one start - and not as good.

''There's a lot of green horses and luck will play a big part on the day, but I think on paper [Criterion] is the best-performed horse in the race,'' Snowden said. ''But it leaves it open now, take him out and the rest are fairly even.''

Unsure of his chances in the Opal, Snowden fancied Sindarin as a sneaky chance of claiming the Canberra Cup.

He said group 1 Sydney Cup winner Niwot was vulnerable this early in his preparation, having had just one run back from a spell.

It was a similar story with Fast Clip (Gai Waterhouse) and Shadows In The Sun (Anthony Cummings).

Snowden thought Sindarin was in ''good order'' and had enjoyed his best preparation.

He admitted the cup was a step up in class for the four-year-old daughter of Redoute's Choice, but hoped the 54 kilograms she was carrying (6kg less than Niwot) would help bring her into contention.

Snowden also said the 2000-metre trip would suit. ''The horses at the top of the weights are the best-performed horses, but they're very early in their preparation,'' he said.

''As I said, they're not fully wound up and they're vulnerable so that might set it up for something down in the weights, so hopefully it's me.''

Canberra Racing took an early hit when acceptances were released on Thursday morning with top two-year-old All The Talk withdrawn.

The Gary Portelli-trained colt will instead target the group 3 Skyline Stakes at Warwick Farm on March 16.

All The Talk ran fourth in the group 2 Silver Slipper at Rosehill last weekend and looked the horse to beat from early nominations.

Canberra Racing chief executive Peter Stubbs said he was still happy with the strength of all the fields - attracted by a record total prizemoney of $766,000 on Super Sunday.