Greenhalgh knows success in the nine-team competition will be tough to earn as the Rams host a strong Hills District Bulls side at Forbes' Spooner Oval on Sunday and more strong rivals lie in wait.

But he has faith that all those who pull on the coveted green and white jumper will be committed.

He points to the last time an open Rams outfit took to the paddock - a narrow 22-20 loss to France last October - as an example of how the best players in the region lift when lining up for Western.

"If we controlled the ball a little bit better in that game I think Western would have done France. I think they [French] were surprised with the toughness and tenacity of people out this way," Greenhalgh said.

"I've said it probably 10 times the last couple of weeks, the talent that's out here in the bush, especially in the Western area, is very exciting.

"There's going to be a lot of players in these [rival] teams who are still affiliated with NRL clubs and we can probably pick a couple of them as well.

"I think if the boys can get their heads around don't worry about who we're playing, just worry about what we've got to do, then we'll be alright."

Having lined up in that match against France, Bathurst brothers Jake and Jedd Betts, Parkes' Jordan Pope, St Pat's Jackson Brien, Forbes playmaker Mitch Burke and Orange Hawks' gun Ethan McKellar all return for the Presidents Cup opener.

They are included in the extended 21-man squad Greenhalgh has named for the Bulls clash. He will trim that to 18 for game day.

In that 18 will be a number of players who represented the under 23s Rams in this year's Country Championships - McKellar and Burke, Wellington duo Brock Naden and Jesse Wighton, Forbes' Bailey Hartwig and Mitch Andrews and Lithgow big man Cody Gooden.

"I've just rewarded a couple of blokes who have been coming to training to start with, we've put together a formidable squad. I don't think we'll be at our best fitness-wise, but we're looking to put in a strong showing," Greenhalgh said.

"There are a couple of fellas who will join the squad at a later date with a bit more experience, but I'm happy with how these fellas are coming along with the rushed program we've got."

While the Bulls' line up boasts plenty of class with the likes of hooker Heath L'Estrange, props Taniela Lasalo and Tim Robinson plus second rower Daniel Harrison all boasting NRL experience, Greenhalgh has faith in his forward pack.

Across three training sessions the coach has "hit them pretty hard" and while they may not have the size of some of their opponents, he feels they have other assets which make them a threat.

"Size does help you out sometimes with go forward and stuff like that, but we are mobile, skilful and tough," he said.

"If you've got a bit of free-running in you, especially in the forwards, then sometimes it can be good."

As well as a talented pack he is happy with, Greenhalgh's back line has plenty of weapons.

There's former NRL and English Super League player Harry Siejka and Group 11 premiership winner Burke in the halves, Mitch Andrews who spent three years in the Newcastle Knights system, and Mackenzie Atkins who toured the UK with the NSW Country under 18s last year.

Given his squad's limited preparation, Greenhalgh said the keys will be execution and perseverance.

"We are just going to try and stay in the picture and minimise our mistakes and try and put 80 minutes together and find a few formula that work for us. We haven't had much time to put anything together and haven't really looked at our opposition, only the names, so it's a bit of an unknown," he said.

"All we can do is go out there and give it our all.

"There are couple of Forbes fellas in the side and Forbes is a pretty footy mad town too, so I'm sure they'll appreciate a bit of local footy."

If all players are fit, Greenhalgh will take his first 18 to Forbes with Taumutu Afemui-Nohotima, Nathan Ward and Ben Lovett to wait for another chance to represent the Rams.

With Wests Illawarra and Thirroul Butchers confirming that they will join the Rams, Bulls, Dubbo CYMS, North Sydney, Maitland Pickers, Wentworthville and Glebe-Burwood Wolves, the competition will be played over nine rounds with two weeks of finals inclusive of a blockbuster grand final weekend on September 26-27.

Sunday's match at Spooner Oval will kick-off at 1pm.