Four years after Playing God's Australian Guineas placing, Perth trainer Neville Parnham is back for another shot at the Group One race.

The Parnham-trained WA Guineas winner Rommel showed he was on track for Saturday's 1600m feature at Flemington with a last-stride win in the Zeditave Stakes.

Parnham had not originally planned to run Rommel in the 1200m Caulfield race but decided it would be better than going into the Guineas second-up with three weeks between runs.

"He's certainly improved off the back of that performance," Parnham said.

"To get up and win was somewhat of a bonus and it gave him a good grounding for this race."

Playing God has been Parnham's only Australian Guineas starter, finishing third to Shamrocker in 2011 before backing up to fill the same placing in the Australian Cup.

He came to Melbourne having won Perth's Group One Kingston Town Stakes as a three-year-old while Rommel was seventh in this season's renewal.

Parnham said Playing God was a more mature horse at the same stage of his career but felt Rommel had blossomed in recent months.

"He's definitely improved off his summer carnival form," Parnham said.

Rommel was ridden by Parnham's son Chris last week but another of his sons, Steven, takes over on Saturday.

Parnham said it was difficult to line up Rommel's form but pointed out that Perth-based galloper Disposition was considered one of the leading Guineas chances before he was ruled out on Wednesday with a minor injury.

"It's a high class field but we're looking forward to the race and hoping he can run up to his best standard," Parnham said.

"I'm sure that's going to see the horse not too far away from them.

"And you never know, we might be able to knock them off."

Rommel is at $13 with most bookmakers who have marked Sydney visitor Kermadec the $3.50 favourite.

Kermadec arrived in Melbourne on Thursday and trainer Chris Waller's stable representative Justine Hales said the colt had coped well with the trip.

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