The Brumbies will announce Cusack's new deal on Thursday, which includes a stint in sevens at the end of the Super Rugby season and the potential of playing at the Tokyo Olympics next year.

Cusack's contract extension is part of the Brumbies' recruitment and retention mission as coach Dan McKellar sets his side for a finals run this year as well as planning for future success.

Playmaker Wharenui Hawera is likely to move his career to Japan, while Lachlan McCaffrey and Matt Lucas are locked in negotiations about extending their Brumbies tenure.

The Brumbies are also working with a host of big names, including Tevita Kuridrani, Christian Lealiifano, David Pocock, Henry Speight and Scott Sio, to determine if they will stay in Canberra after the World Cup in Japan this year.

Cusack had a trip to Japan in the back of his mind for a different reason: the 2020 Olympics. The 26-year-old first made a name for himself in sevens and was named in the Rio Olympic all-star side three years ago before switching to Super Rugby.

But he has always been a sevens target and could force his way into the Olympic side if he performs well enough when he returns to the code in the coming months.

His Super Rugby move has been a success and Cusack has become one of the Brumbies' most reliable players, particularly in Pocock's absence for most of this season.

Pocock will likely miss the Brumbies' clash against the Japan Sunwolves on Sunday as he continues to battle a calf problem, which has crippled what could be his final season in Australian rugby.

The champion openside flanker is yet to make a decision about his long-term future and whether he will continue his rugby career beyond the Wallabies' World Cup campaign.

Cusack has proved a capable replacement, while the Brumbies are also expected to sign NSW flanker Will Miller. Young gun Rob Valetini has already re-signed and McCaffrey is keen to stay in the capital.

The Brumbies' back-row depth has been seriously tested this season with Pocock playing just three games, Ben Hyne being ruled out for the season and Valetini and McCaffrey both missing matches because of injury.

McCaffrey is in contention to make his comeback from a knee problem this week, with McKellar to name his side on Friday before another must-win match at home.

Kuridrani is also trying to prove he is fit after missing last week, but the 20-year-old who filled in at outside centre stepped up to launch his own Super Rugby career.

Len Ikitau was given the outside centre job last week and didn't let the Brumbies down, earning praise from McKellar, Lealiifano and former Wallabies Drew Mitchell and Stephen Hoiles.

The former junior Wallabies back is understood to be on the Brumbies' radar for a contract extension, and Ikitau hopes a one-game taste of professional rugby ignites his career.

"Getting my first cap was a goal I set at the start of the year and it was such a great opportunity," Ikitau said.

"The boys told me to back my skills. To be able to play for the Brumbies was something I'll remember forever.

"I really look up to Tevita, he's a fantastic player. I know you can't replace him, so I just wanted to do my job for the team and I'm looking forward to what's next."

The Brumbies will wear a special Mother's Day jersey on Sunday, with players to have the names of their mums stitched on to the back of their jumpers. It is hoped afternoon rugby will attract a big crowd to the clash.

SUPER RUGBY ROUND 13

Sunday: ACT Brumbies v Japan Sunwolves at Canberra Stadium, 4.05pm. Tickets available from Ticketek.