With the Matildas custodian ruled out of the upcoming W-League season with a knee injury, MacKenzie Arnold and Trudy Burke are in line to fill her gloves for the club's title defence.

Having worked with Williams before as part of the Young Matildas squad, Arnold is keen to learn from her idol this season.

''I've always looked up to Lydia from under 17s and she's always been there,'' Arnold said.

''It's good to train with her at the Aussie camps. She's a real motivator and gets me going.''

Although only 18, Arnold already has a full W-League campaign under her belt.

The Gold Coast native endured a tough season with minnows Perth Glory, which apart from conceding plenty of goals also had two players leave mid-season for disciplinary reasons.

''There were a couple of hiccups with the team, but it was good,'' she said.

''It's an experience that is only going to help me as a player.''

Burke got a taste of the W-League as a replacement goalkeeper for Sydney FC in last year's semi-final, sitting on the bench in its penalty shootout loss to Brisbane Roar.

This is her first full-time gig in the national competition, having honed her skills with the Illawarra Stingrays and currently with the Macarthur Rams.

The 21-year-old can't believe her luck in joining a club gunning for consecutive titles.

''It's crazy, really. I'm stoked to be here,'' Burke said.

''Canberra United is going for back-to-back, so it's unreal to get an opportunity and be amongst it.''

Both prospective custodians have arrived in Canberra for pre-season training with Matildas and United goalkeeping coach Paul Jones ahead of the start of official training on September 21.

United starts a season with no definitive first-choice goalkeeper for the first time in its history.

Williams has held that mantle since the inaugural campaign, not missing a match in the W-League's four seasons.

Burke believes the friendly competition for the No.1 jersey can only be a positive.

''It'll be great to push each other along and get the best out of each other,'' she said.

''There's a little bit of pressure, but it's good.

''It keeps you on your toes, wanting to improve yourself and go one better and see how far you can really push yourself.''