Marsh had hoped Jason Waddell would take the mount in the $230,000 1600m but he couldn't make the horse's 52.5kg.
He also struck out in booking last-start pilot Noel Harris who was already committed to race rival, outsider Comanche Gold.
"With the lightweight he's got we were stuck for options over here so we thought we'd fly the best over and hope he'll do the job for us."
Walker's most recent trip to New Zealand was on Wellington Cup Day at Trentham and Karaka Million night at Ellerslie when he partnered the Marsh-trained Hogwarts Express into seventh placing in the $1 million 2-year-old feature.
More recently he has been in hot demand in Victoria, finishing an unlucky third on Rawnaq in the group one Victoria Derby.
A week later, he took full advantage of a replacement ride for the suspended Luke Nolan to win the Momentum Energy Trophy aboard Good Value at Flemington on Saturday.
Soon after his return to New Zealand, Walker intends to take a few weeks off for surgery on a hip that has troubled him for a few years.
But Marsh is confident he can send him to the sidelines on a group two high.
Savour The Moment emerged as a future mile headliner at the same carnival last year, running second on the first day in a R75 1400m before backing up a week later with victory in R85 company over 1600m.
He was even more impressive when completing a hat-trick at Te Rapa over the same trip the following month.
Marsh gave him just two further runs in that campaign, for eighth as a $5.70 fancy in the Rich Hill Mile at Ellerslie and second to Say No More back in R85 grade at Awapuni.
"Has been quite a slow maturing horse but he did very little wrong in his last campaign," said Marsh.
"In his final race he was enormous and he was under an injury cloud that day; he pulled up a bit sore.
"We thought he'd win but he was beaten by Say No More. We were probably a bit disappointed but then she came out and won the group one Thorndon Mile after that so there was nothing to be disappointed about at all."
The Savabeel 5-year-old resumed with a blow-out for fourth over 1400m at Taupo on October 10 before confirming a Riccarton trip with an unlucky equal third behind Coupland's rivals Undisclosed and Shuka over the same trip at Ellerslie on October 27.
"I thought his Ellerslie run was super," said Marsh.
"He didn't have much luck at all and he's actually a lot better horse going left-handed.
"He was held up a bit at the 300m but still attacked the line really well. He's come through it really well and is looking really good for Wednesday I must say."
Marsh is hoping it's the start of a career-high week.
He also saddles exciting Darci Brahma filly Lucky Country in the $300,000 1000 Guineas (1600m) at Riccarton on Saturday, chasing his first group one success as a solo trainer.
Lucky Country, who arrives in Christchurch on a flight tomorrow, has had just four career starts but half of those have been at Riccarton.
She kicked off with a third there last April before failing next-up at listed level in the Champagne Stakes.
But since she returned to racing last month with a winning double, the penny has well and truly dropped.
"Everything she's done this time in has been faultless," said Marsh.
"It's a good field but she's got to be a good chance too. I'd just love to see her get a good draw. I think a good draw is vital for her.
"Fingers crossed. The horses are going great guns. A little bit of luck on our side and it could be a great week."
