Trainer John McArdle has the routine down pat when he sends Themoonlitegambler to the races in South Australia.

Themoonlitegambler's latest foray is for Saturday's Group One South Australian Derby (2500m) at Morphettville and follows the three-year-old's past two Adelaide starts in the Port Adelaide Guineas and Chairman's Stakes.

Each time Themoonlitegambler has left McArdle's Mornington stable on Thursday night, returning on Sunday.

Both times he has been placed behind Derby favourite Dalasan.

McArdle is hoping for a better result on Saturday, but the routine is the same.

"He's a bit of a finicky fella. He prefers to come home and be in his own surroundings," McArdle said.

Themoonlitegambler has drawn barrier one on Saturday and will be ridden by Dean Holland, replacing Emily Finnegan who was aboard the gelding in his two previous starts.

McArdle is hopeful Themoonlitegambler will settle better for Holland, saying the the gelding can get a bit strong in his races.

"Emily's done nothing wrong other than she probably got going a little bit earlier on him than what we wanted," McArdle said.

"He can pull a bit hard and get a bit strong so we've elected to go with the more experienced and a little stronger jockey.

"From barrier one he should get a good run. He looks as though he's going to be able to run the trip, but we'll try and get out and get rolling from about the 500 metres and see if he can stay."

McArdle said Themoonlitegambler had come a long way since his debut third behind fellow Derby aspirant Russian Camelot at Ballarat last October.

"He had no idea what he was doing that day," McArdle said.

"That was 1400 metres. It wasn't ideal, but he's come a long way since then and he'll be there on Saturday trying his heart out.

"But he'll be a better horse in 12 months time and again as a five-year-old as he's still got to mature up a bit.

"It's not an easy race.

"Dalasan is a very well-credentialled horse, Russian Camelot looks like he could be anything, then there is Warning, a Victoria Derby winner and Mitch Freedman's horse Moonlight Maid was good in the Oaks last week.

"He's going to have to be at his best, but so will they."