Kopmeyer, 27, currently plays for in the NWSL with Seattle Reign and has previously played in the W-League with the Brisbane Roar.

United were minor premiers last season before bouncing out in the semi finals and first-year coach Garriock said tightening up their defence is the major focus and it starts with Kopemeyer.

"The importance of having a strong goalkeeper in the W-League is massive and obviously we're limited in quality of goalkeepers in Australia so it was crucial to find a good competent one in Haley," Garriock said.

"She brings leadership, experience, work ethic and obviously great ability in goals. Securing a quality goalkeeper was my number one priority because we've been a very good side in the past at scoring lots of goals, but the weakness was the defensive discipline."

Kopmeyer will arrive in the capital following the conclusion of the NWSL season in October and said she can't wait to get started at United.

"I've heard wonderful things about the club, it's professionalism and new coach in Heather. It's a perfect fit for this time in my career and I'm excited to help the team compete for the title," Kopmeyer said.

"My first year in the W-League was instrumental to my development as a goalkeeper and being able to return a few years older, I hope to make a large impact."

Meanwhile, the Matildas host Brazil in Sydney on Saturday for the first time in Matildas history, coach Alen Stajcic could field an entirely foreign-based side.

"Everyone has shown a bit more interest in going overseas this year without a major tournament like the World Cup or Olympics," Japan-based midfielder Katrina Gorry said.

"It's to get the experience and better different parts of our games. I think that's really shown in our performances across the board."

At the Tournament of Nations last month, which Australia won, Stajcic came close to his first foreign-based XI.

The 14 players used to beat world champions USA contained just two Australia- based players - both with the talent to play abroad.

One, emerging Canberra defender Elise Carpenter, is just 17 and has plenty of time to forge an overseas-based career.

The other is legendary striker Lisa De Vanna - who has played in England, Sweden and USA - but played her club football with state league club South Melbourne this season as part of a management plan to extend her career.

At the other end of the spectrum, Elise Kellond-Knight, playing with table- topping German club Turbine Potsdam, has enjoyed a pre-season playing against European heavyweights Arsenal and Paris St Germain.

"To get a bit of exposure against elite European clubs, I've really enjoyed that," she said.

"In the two years I've been there it's been a rollercoaster with good times and bad ... but I feel like I'm developing and learning. That's why I've stayed."

Club commitments are likely to rule out Kellond-Knight from the upcoming W-League season, but Gorry says she'll be back with Brisbane Roar.

Steph Catley will also return home to captain Melbourne City the conclusion of her overseas season with Orlando Pride.

Catley is one of five US-based Matildas, led by goalscoring wonder Sam Kerr.

Her stint at the Pride - alongside Matildas defender Alanna Kennedy - has also allowed her to get the low-down on this week's opponents.

Three of Brazil's squad, including five-time world player of the year Marta, are part of the title-chasing Pride.

"Marta is an incredible player and really hard to mark. Fortunately training with her so I know what's coming," Catley said.

with AAP