Three-year-old Savvy Nature will not take his place against the weight-for-age heavyweights in Saturday's $1.5 million BMW.

Managing owner Max Whitby entertained the notion of backing him up after the gelding finished fourth in the Rosehill Guineas behind Criterion, believing he might need another solid hit-out before the Derby.

After talking with John O'Shea on the trainer's return from the Dubai World Cup meeting, Whitby said Savvy Nature would have his next start in the $2 million Australian Derby (2400m) on April 12 as planned.

"He looked like he needed 4000 metres but I calmed down after talking to John," Whitby said.

"We'll stick to the original plan."

That leaves the Anthony Cummings-trained Surge Ahead, seventh in the Guineas, as the only three-year-old among the nominations for the 2400m race.

Cummings won the 2013 BMW with three-year-old Fiveandahalfstar who was better performed than Surge Ahead in a race without as much class as this year's event.

Although it has had a prize money drop of $750,000, the BMW will feature 2013 Melbourne Cup winner Fiorente, five-time Group One winner It's A Dundeel and Silent Achiever who upset them in the Ranvet Stakes.

Also in the mix is 2012 Melbourne Cup winner Green Moon and his Lloyd Williams-owned Robert Hickmott-trained stablemate Mourayan, winner of last year's Sydney Cup.

Queensland Derby winner Hawkspur will be a non-acceptor on Wednesday with his program switched to the Doncaster Mile a week after the BMW.

Silent Achiever's trainer Roger James said the mare had pleased him with a comfortable workout on Tuesday.

The 2012 New Zealand Derby winner is unbeaten in three starts this campaign, two at Group One level.

James says the difference has been the addition of blinkers which have helped the five-year-old race in a more forward position.

"I was tempted to put them on in the spring but she was racing well without them so I didn't want to change anything," James said.

"But this time she has shown she can get up handy in her races and they have made a big difference."