After guiding Rulership to an easy debut victory at Randwick, Nash Rawiller has been replaced by Mark Zahra in the colt's upcoming Melbourne races.

Impressive debut Randwick winner Rulership will have a new rider when he heads to Melbourne to prepare for the Blue Diamond Stakes at Caulfield.

Nash Rawiller rode the Peter and Paul Snowden-trained two-year-old to win on Saturday but has already been told Mark Zahra will ride the colt in Melbourne.

Rulership is scheduled to start in the Blue Diamond Prelude (1100m) at Caulfield on Saturday week ahead of the Blue Diamond Stakes (1200m) on February 22.

The father-and-son training duo last won the Blue Diamond with Pride Of Dubai in 2015.

"I've already found out that I've been overlooked for Melbourne," Rawiller told RSN927.

"I was already booking my plane ticket but Zahra is going to ride him.

"I don't think I ride too bad at Caulfield, it's one of my favourite tracks."

Rulership shares the second line of betting with Fresh at $8 for the Blue Diamond with unbeaten Anthony Freedman-trained colt Hanseatic the $3.50 favourite.

Rawiller says if Rulership returns to Sydney for the Golden Slipper at Rosehill in March, for which he is a $26 chance, he hopes to be reunited with the colt.

"These things only make you tougher and more determined," Rawiller said.

"He's a horse that could that could go to the elite level and you never know what could happen down the track."

Rawiller says he has a few other two-year-old options on the horizon but none are so far showing the class of Rulership.

"There's a few that I've ridden that have shown promising ability but nothing at the moment like this horse for the big two-year-old races coming up," Rawiller said.