McKellar is spending time with an NRL powerhouse in the Melbourne Storm and the Brisbane Broncos in search of ideas to help spark the Brumbies amidst a changing of the guard.

It comes as Australia's most successful Super Rugby club officially unveil the signing of Will Miller, from Berry, as McKellar looks to fill the boots left by the world's best openside flanker.

Miller says the decision to join the Brumbies on a two-year deal was a "no-brainer" as they look to plug the gap left by David Pocock.

The 26-year-old is yearning for a consistent Super Rugby start having been stuck behind Wallabies captain Michael Hooper at the NSW Waratahs this year.

He has a chance to find just that when he joins the Brumbies ahead of pre-season training in November and jostles with the likes of Tom Cusack for the No. 7 jumper.

McKellar's task to replace Pocock may not be as daunting as it seems.

Pocock managed just 43 games in his seven-season stint at the club and McKellar says the Brumbies are blessed with solid depth in the back-row.

"We've got a very good group of back-rowers and we tend to have had that for a number of years," McKellar said.

"Cusack is there, Jahrome Brown played 7 this year, Will Miller is now thrown into that bunch as well, along with [Pete] Samu, [Rob] Valetini and [Lachlan] McCaffrey.

"It's certainly going to be good competition for those back-row positions."

Miller has 34 Super Rugby caps to his name across three seasons with the Waratahs and Melbourne Rebels.

He has come a long way since McKellar first laid eyes on him tearing apart the club rugby scene in Sydney.

"I watched him closely a few years ago when he was a dominant player at club level for Norths [in the Shute Shield]," McKellar said.

Related content: 'The decision became a no-brainer for me': Miller

"We're excited to have him come to the Brumbies. Obviously when you lose David Pocock, you need to replace him, and ideally with someone who has that on-ball presence.

"Will certainly has that, as well as many other areas of his game that are of quality.

"A good part to his game is his leadership. He is considered to be someone who reads, understands and knows the game well.

"Those are the sort of players we want to bring into our group."

McKellar's squad is not yet settled as they look to build on their semi-final exit with his sights set on a lock and a handful of backs.