It can be revealed Staniforth has signed a deal to join the Waratahs as they prepare to fill the holes left by departing duo Dean Mumm and Will Skelton, with an announcement expected in the coming weeks.

Canberra junior Staniforth grew up dreaming of playing for the Brumbies and his decision to join the club's bitter rivals would usually be considered treason.

But the Brumbies have given Staniforth their blessing to chase more game time in Sydney after being stuck behind Sam Carter, Rory Arnold and Blake Enever in the capital.

Staniforth's move follows news veteran Saia and Anthony Faingaa will leave the capital to play for London Irish and the Kintetsu Liners respectively while Jordan Smiler has signed a deal with Suntory.

The Brumbies are set to bolster their own ranks in the coming days with a long list of re-signings set to emerge as they build a roster for the future.

The Brumbies have been locked in negotiations with more than 20 players after the ARU lifted its ban on registering contracts.

Hooker Josh Mann-Rea, Tevita Kuridrani, Tomas Cubelli, Jarrad Butler and Ben Alexander are part of a group of off-contract players.

But the chance to get more game time and a regular Super Rugby spot at the Waratahs convinced former Australian under-20s vice-captain Staniforth to join NSW.

Before he goes, the hard-working former Canberra Grammar student will play an important role as the Brumbies chase a Super Rugby title in July.

The Brumbies secured their place in the play-offs for a fifth consecutive season when they beat the Melbourne Rebels last weekend.

But the bonus-point win also doubled as a farewell game for scrumhalf De Wet Roos, who returned to his work as a construction project manager after a four-month stint at the Brumbies.

Roos was acting as cover from Cubelli after the Argentinian international injured his knee in a pre-season game.

Cubelli is expected to make a comeback from the last two games of the regular season, starting with a clash against the Queensland Reds on July 7, and will end Roos' tenure.

Brumbies coach Stephen Larkham says the club will maintain contact with Roos, leaving the door open to recalling the 26-year-old if needed.

"It's been pretty good, I really enjoyed it and learnt a lot, it's been a really good experience for me," Roos said.

"I'll go back to the day job and club-land in Sydney to play for Southern Districts, hopefully we can get into the semi-finals there and just keep working.

"I'll stay in touch with the Brumbies in case they need some injury cover or anything like that.

"I've just got to go back and be ready if and when a call up comes."

Roos has been an important background player behind the rise of No. 9 Joe Powell, who is expected to make his Wallabies debut against Fiji on Saturday night.

Roos played in 10 games and averaged eight minutes, but his impact from the bench gave the Brumbies spark at the end of matches.

"When I got out there it just felt normal and I wasn't too nervous which was good," Roos said.

"It gave me confidence that I am ready for Super Rugby if needed. I got a bit of everything this season, I'll take it on board and see where we go from there."

Cubelli will join Powell and Ryan Lonergan as the Brumbies' contracted scrumhalves.

"Through this period De Wet has been a real energy ball to the team - he's lifted spirits and done everything we've asked of him," said coach Stephen Larkham.

"He couldn't have been a better professional player if he tried. It's disappointing he goes now, but we'll stay in touch and make sure we don't lose that ability to call him into the squad at a moment's notice."