In contrast to last year, Craig Newitt is going into the Victoria Derby on a horse he has never ridden in a race before but is confident Captain Duffy is a realistic chance to give him successive victories.

Newitt was the only jockey to ride the recently-retired Tarzino who was the overwhelming favourite in 2015 and duly delivered.

He has picked up the ride in the blue riband this year on the Phillip Stokes-trained Captain Duffy with Noel Callow ruled out because of a concussion suffered in a fall on Tuesday sidelining him for five days under the rules.

While Tarzino was sent out the $2.90 favourite in 2015, Captain Duffy is an $18 chance in a market dominated by Sacred Elixir at $2.80.

But that doesn't concern Newitt.

"I reckon he's a good chance," Newitt said.

"I went into the Derby last year thinking the only way I would get beaten was if I fell off Tarzino.

"The way this horse is going, the gate he's drawn (2) and the run he's going to get, I can't see him missing top four."

Newitt partnered Captain Duffy in trackwork at Caulfield on Thursday morning before heading to Werribee to ride Grey Lion in a gallop ahead of next Tuesday's Melbourne Cup.

Newitt said if you didn't know Captain Duffy was a Derby contender you would think he was lining up against the sprinting three-year-olds in Saturday's Coolmore Stud Stakes.

"He wants to go one hundred miles an hour on the track but on raceday he's completely the opposite," Newitt said.

"This bloke is going to get a similar sort of run to last year and as we know if you can stay the trip you're half a chance.

"I reckon he's one of a few that is guaranteed to run it."

Captain Duffy proved his endurance when he won last week's Geelong Classic over 2400 metres, beating Derby rival Hollywood Mo by 1-1/4 lengths with Pretty Punk, who runs in the Wakeful Stakes on Saturday, third.

Tarzino was trained by Mick Price who has Rocketeer in this year's Derby with Mark Zahra to ride.

Rocketeer won a Wangaratta maiden in August and has racked up four seconds at his latest four starts.

He is a $16 chance and will start from the second-widest barrier.

Price is under no illusions about the task ahead but says the gelding is fit and healthy.

"It's not the same feeling as last year but the horse is the best he's ever been," he said.

"His coat is right and he's great in himself.

"I've backed off his work because he seemed fatigued after the UCI Stakes two starts ago and it seems to have worked."