Apprentice Patrick Moloney has been entrusted with the ride aboard Furnaces for the three-year-old's weight-for-age debut at Moonee Valley.

Furnaces will also be having his first run in Melbourne when he lines up in the Group Two McEwen Stakes on Saturday.

Moloney has been riding the majority of trainer John O'Shea's Melbourne horses and has been rewarded with the ride in the Group race.

"It's a big opportunity for an apprentice, especially at this time of year with the spring carnival on our doorstep," Moloney said.

"I ride in jump-outs for (Godolphin) on a Friday or whenever they ask me for a gallop like they did with Furnaces at Moonee Valley."

Moloney gave Furnaces a workout at Moonee Valley on Tuesday with stablemate Bantam, running 800m in 55.09secs, coming home the last 400m in 24.3secs.

"He handled Moonee Valley well but we weren't going quick and I can't see why he won't adapt to this way of going in a race," Moloney said.

A winner on debut at Rosehill and a last-start winner of the Kindergarten Stakes at Randwick in April, Furnaces ran sixth behind Vancouver in the Golden Slipper.

O'Shea was at Moonee Valley to watch the workout and was happy with what he saw.

"He was good and relaxed and worked up the straight well," O'Shea said.

"He came off the bend well and pulled up really well most importantly and goes into the race on Saturday with a nice chance."

Furnaces shares the second line of betting at $7 with Kuro and Sistonic behind the $2.10 favourite Chautauqua.