Chris Waller agrees with punters who have made Diametric the Parramatta Cup favourite but as usual in Sydney distance races the trainer has multiple runners.

The stable has six runners in the 1900-metre Listed race at Rosehill on Saturday - Diametric, Our Voodoo Prince, Permit, Secessio, Black Jag and Grand Marshall.

Diametric, who will be ridden by premiership leader Blake Shinn, is at $4.20 with the Gai Waterhouse-trained Pajaro being kept safe at $6 as the first emergency.

"Some have just about reached their full potential and some are looking for further," Waller said.

"Diametric is probably our main chance but there will be no excuses for Black Jag.

"I was disappointed he didn't win last start."

The third elect alongside Greatwood at $6.50, Black Jag led over 2000m but was run down to finish a half length second to Centre Pivot.

His most recent of eight wins came in June last year but in eight starts since he has racked up a frustrating four minor placings.

French import Diametric notched his first Australian win in January when he was awarded a 1600-metre victory at Randwick after a successful protest by Shinn against The Alfonso's jockey Tye Angland.

Diametric ran fifth as favourite last Saturday week over 1600m, a distance both Shinn and Waller said was now too short.

His three wins in France were from 1900m to 2100m.