History might turn out be a more formidable obstacle for It's A Dundeel than any challenge his remaining seven Rosehill Guineas rivals can mount after the defection of Fiveandahalfstar from the Group One classic.

Trainer Anthony Cummings made a Guineas call on Fiveandahalfstar earlier than expected, scratching the Victoria Derby winner on Friday from a race in which he was a clear second favourite behind his New Zealand rival.

Fiveandahalfstar will now head towards next week's $2.25 million BMW with Cummings saying he has got his timing right for the weight-for-age staying test.

"Once I decided to gallop him today it put tomorrow out of the question," Cummings said.

"I am thinking his gallop this morning and another one on Sunday will probably get him to where he needs to be without having to worry about running on Saturday."

In Fiveandahalfstar's absence, It's A Dundeel promises to start one of the shortest-priced Guineas favourites since the race was shifted to an autumn date in 1979.

He was already at a red-figure quote with Fiveandahalfstar in the field but is now in rarefied territory as a $1.45 chance to emulate Metal Bender's Randwick Guineas-Rosehill Guineas double of 2009.

But odds-on favourites have a chequered history in the race, none more so than Dignity Dancer who was sent out at $1.50 in a similarly small field only to succumb to Sky Heights in 1999.

It was an even worse result for the only odds-on runner since with Universal Prince ($1.80) finishing midfield in 2001.

Craig Newitt is one rival jockey who isn't conceding the Guineas is one-horse race as he returns from suspension to ride Hvasstan, now $7 second favourite in the TAB's reshuffled market.

"I've got a lot of time for him," Newitt said.

"My first ride on him was in the Australian Guineas where he was the best run in the race by a hundred yards, and then he came out and franked the form by winning the Alister Clark.

"All reports are he's improved again."

Hvasstan finished two lengths in front of It's A Dundeel when they met for the only time in the Victoria Derby, a result that has Newitt entertaining the prospect of a Guineas upset as confirmation of the horse's Australian Derby chances.

"I'm expecting my bloke to be very hard to beat on Saturday and especially hard to beat in the Derby," he said.