But while there's still a glimmer of hope for selection, the inaugural Canberra United captain is throwing everything she's got towards a Matildas recall.

Like the great John Farnham, Brush has come out of retirement and re-signed with Sydney FC in a bid to play at next year's Olympic Games.

But to focus on her Tokyo ambitions with the Matildas, she's also had to step away from her AFLW career and ended her time as a dual-code star.

Brush played 20 games over four seasons with the GWS Giants, splitting her summer between the two football codes.

A part of her felt guilty for prioritising the W-League last season, with the 31-year-old Canberran playing 14 games for the Sky Blue.

"It puts a bit of weight off my shoulders knowing I've got the one sport and team to focus on and put all my energy into," Brush said.

"A big part of that was the Olympics being postponed and it gave me a chance, I feel like I have another shot at the Matildas for the Olympic team.

"Its postponement, though terrible, felt like it was a little sign... personally it's given me another glimmer of hope for that dream."

Brush considered retiring from W-League at the end of last season, but the postponement of the 2020 Olympics has given her a second chance to push for higher honours.

She has two international caps and hasn't played for Australia since 2009, but is adamant her best days could still be ahead.

The majority of the Matildas' regular playing squad, including Queanbeyan junior Karly Roestbakken, has moved to Europe to ply their trade against higher-quality competition.

Brush considered following suit but decided to remain in Sydney as her father battles cancer.

"Sometimes things are bigger than football, you only get so long with your loved ones," Brush said.

"I'd hate to be stuck overseas and he's in hospital or something terrible happens. That's the thing I would regret forever."

She admits breaking into the Australian squad will be a tough ask under the circumstances, but is determined to enter the selection frame while there's still a chance.

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The Matildas coaching vacancy left by Ante Milicic has also given Brush hope, with the defender eager to impress the incoming mentor.

"It'll be tough, there's no doubting that. I acknowledge I've only got a very small glimmer... it's a tiny chance but while there's a chance I'll continue to pursue that," Brush said.

"I've been talking with my Sydney FC coach [Ante Juric] during the off-season about areas of my game I can work on. It's been really helpful to work with him and try to get the most out of myself, to give myself the best opportunity.

"There's also a new Matilda's coach coming in, so hopefully they'll look at everybody - a set of fresh eyes can be really helpful for a team."