Smith arrived in Canberra on Monday to start a two-year deal with the Brumbies following his Super Rugby off-season campaign with the Toyota Verblitz.

But there's something missing as the 26-year-old prepares to play without identical twin brother Jean-Pierre by his side for the first time in four years.

Smith is one of a handful of Super Rugby players who used the off-season to boost their earnings and play in the lucrative Japanese competition.

It's set to become a well-worn path, with the ARU introducing flexible contracts to ensure players aren't poached permanently, with Bernard Foley, Israel Folau and Brumbies co-captain Christian Lealiifano all taking up the option.

The risk of the continuous season without a solid training block is that players will burn out eventually.

But Ruan Smith is driven by his desire for more Brumbies game time and the battle with Ben Alexander, Les Leuluaialii-Makin and Tyrell Lomax for tighthead prop positions.

"For me personally, I think this year is going to be hard. But more mentally," Smith said.

"For the [back-line] players it's very reasonable because it's not as physical in Japan. But for forwards, you still have to do the hard work. Maybe two or three years of doing it would be maximum.

"It takes a toll at the end of the day because you miss pre-season, which is where you make your gains and get your body right. It depends how you manage it."

Smith timed his comeback perfectly, with Australian scrum mentor Mario Ledesma a surprise visitor at Brumbies training on Tuesday to cast his eye over the forward pack.

Smith is set to be thrown straight into action less than a week after walking out of the Japanese winter and into the Australian summer.

He will play against the NSW Waratahs in a trial match in Wagga on Saturday night, with tighthead prop game time rotated among Alexander, Smith and Leuluaialii-Makin.

Smith will wait until later in the year to see how his body is coping before making any decision about whether he will return to Japan .

The South African-born giant admitted there was a strange feeling when he returned to Brumbies headquarters on Monday when he sat down at his locker and brother Jean-Pierre was absent.

Jean-Pierre has returned to South Africa to join the Cape Town Stormers.

"It is different ... his name is still on the locker right next to me. We used to come in together and leave together, so I will miss that," Ruan said.

"He made that choice for something different like I did for Japan. I'm alone now ... JP used to be a bit of a nuisance. But the stint in Japan has helped me dealing with that."

The Brumbies will name an extended squad for the clash against the Waratahs, with coach Stephen Larkham to rest a host of Wallabies stars.

New co-captains Lealiifano and Stephen Moore will miss the match.

Canberra Vikings skipper Jarrad Butler and playmaker Matt Toomua loom as two of the candidates to take charge.

Smith said playing in Japan "has changed the perspective of how I should play and approach things".

"I think I'll benefit from it," he said.