Brumbies coach Dan McKellar has been working to complete his roster after Rugby Australia said it would likely increase squad sizes and the $5 million salary cap for next season.

The Brumbies are prepared to swoop and will add more players to their squad next week, but they have landed an early addition to add young power to their forward pack.

The Melbourne Rebels continued their Force signing spree on Thursday, recruiting Billy Meakes, Matt Philip and Richard Hardwick to their squad.

The Brumbies will start pre-season training at the end of next week as McKellar finalises his roster puzzle.

Several players are itching for chances to impress, including Lachlan McCaffrey, who has taken an unconventional path to the Brumbies for a fourth Super Rugby chance.

McCaffrey has played for three Australian teams, two teams in England and was a candidate for the seat of Bennelong at the 2013 federal election in the seven years since making his Super Rugby debut.

But the 27-year-old is back in Canberra for one reason - to prove he can be a regular Super Rugby back-rower.

McCaffrey hopes to reignite his Australian career at the Brumbies after finishing a three-season stint in England with London Welsh and the Leicester Tigers.

It will be his fourth attempt to establish himself on a Super Rugby roster after previous stints with the NSW Waratahs, the Force and the Brumbies in 2014.

He hopes the difference this time is the valuable experience he got overseas will help him take the next step in his career.

"I've always wanted to play at the highest level in Australia, whether that's playing Super Rugby every week or higher than that," McCaffrey said.

"That's one goal I haven't achieved yet. I think I went overseas earlier than I would have liked, but I went to get opportunities I wasn't getting Australia.

"I got 70 or 80 premiership and European Cup games in three years, that's what I was after. I got a lot out of it, but at the end of the day I wanted to come back here.

"I thought the Brumbies were the best option to give me a chance of achieving those goals."

The Brumbies will finalise their squad in the coming weeks, with three more players expected to join the club in the wake of the Force's Super Rugby demise.

Fijian-born back-rower Isi Naisarani has signed a deal to join the Brumbies and his arrival will set up massive competition for Brumbies selection.

Naisarani and McCaffrey will compete with David Pocock, Tom Cusack, Lolo Fakaosilea and young gun Rob Valetini for starting spots next year.

The Brumbies will start Super Rugby pre-season training at the end of November, with Pocock to return in January after finishing his Australian rugby sabbatical.

"My previous stints were stop-start. I played a little bit, but I never cemented a starting spot," McCaffrey said.

"The fire still burns. I've always thought of coming back, it was just a matter of time and I think I maximised my opportunities overseas.

"I think I've grown as a player a huge amount and can't wait to have another crack."

Former Brumbies head coach Laurie Fisher is back in Canberra and will join Dan McKellar's staff as the forwards mentor.

Fisher has returned to the club after a stint with English club Gloucester and got a chance to watch McCaffrey develop.

"He developed massively as a player over there ... he's a good communicator and reads the game, but I thought he was much harder on the ball over there," Fisher said.

"We've got tremendous competition in that back row with continuing players and then Poey, Naisarani and McCaffrey coming in.

"They're just going to have to fight for a position, which is great."