Lonergan is set to sign a contract extension on Tuesday, securing the 20-year-old's future at the Brumbies just days after scrumhalf teammate Matt Lucas agreed to a short-term stint with Japanese club Suntory.

Lonergan has been earmarked as a future Wallaby and led Australia into its junior World Cup campaign in France earlier this year.

He made his Brumbies debut as a teenager last year in the last game of the regular season, but was forced to bide his time on the fringes behind Joe Powell and Lucas this year.

The Brumbies view him as a long-term prospect and he is part of an emerging group of youngsters who are set to be rewarded with contracts, including prop Tom Ross and speedster Len Ikitau.

The Brumbies are also expected to finalise a deal to lure Irae Simone to Canberra after the inside back was released by the NSW Waratahs when their Super Rugby season ended last weekend.

Coach Dan McKellar will keep the core of his squad together for next year, allowing him to promote juniors to help usher them into a Super Rugby program.

Simone has been recruited to add depth at inside centre after the departure of Kyle Godwin, while McKellar is also searching for back-line strikeweapons to fit into an attacking game plan.

Lucas is hoping his time at Suntory will boost his chances of more game time next year given the fast-paced Japanese style suits preparations for the way the Brumbies want to play.

Lucas will team up with Brumbies great Matt Giteau as Suntory attempts to defend its Top League title this season.

"It's a good chance to come over and play some footy in a different sort of style, an up-tempo game that will help me develop other parts of my game," Lucas said.

"It was a good opportunity to do something different and a good avenue to continue developing. I've got to improve certain aspects of my game and Suntory enjoys that up-tempo style.

"I really enjoy Japan, it's a really good way to freshen up over here. I'm not in need of a break from footy at the moment and this gives me a chance to play right up until the New Year."

Lucas will miss a large chunk of the Brumbies' pre-season and the National Rugby Championship campaign. But his absence will allow Lonergan to start at No. 9 for the Canberra Vikings while Powell is in Wallabies camp.

The trio will team up again next year and compete for game time as Lonergan, who is aiming to lead the Tuggeranong Vikings to a Canberra premier division premiership, looks for an opportunity to launch his career.

Lucas played 16 games for the Brumbies this year, but had just two chances to start games and averaged 22 minutes from the bench.

He will play alongside Sean McMahon and former Brumby Jordan Smiler, but he says he's most looking forward to working with 103-Test Wallaby Giteau.

"To learn off those guys, and Gits more importantly, is only going to help my game. To see how he carries himself and how he operates, and then get to play alongside him, will be huge.

"I don't think you can put a limit on what I'll be able to learn from him. That's something I'm really excited for."