American striker Katie Stengel has been ruled out of Canberra's round-six clash with Adelaide United on Sunday, with the 27-year-old nursing an ankle injury.

Stengel has played just three games so far this season due to injury and wore a moon boot to training this week.

United has seven matches remaining in the regular season and the club has decided to rest the striker for three weeks.

The club has remained tight-lipped on the extent of the injury but depending on her recovery, Stengel might not be available to play seven matches in total.

If that scenario arose, United could revisit Thorsnes' contract to keep the Norwegian veteran in the capital longer-term.

Thorsnes signed as a guest player, meaning she can only play seven matches during the season.

If she plays seven consecutive games, her final match will be against Melbourne City on January 9.

The only way Canberra can keep her on a longer-term contract will be if there are injuries or another international departs.

But Canberra coach Heather Garriock says the club won't enter talks prematurely, with Stengel's welfare being of paramount importance.

"I still haven't really thought about it at the moment, only because I think it's important we have full faith Katie will recover and be able to get her back on the park," Garriock said.

"If I have any conversations in and around that, then I think it would not be fair on Katie. Her health and wellbeing is the most important thing.

"Elise mentioned to the media last week that she should love to stay but there's so many factors from a national team perspective and our own perspective at Canberra United. She's a great player."

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This week with be Thorsnes fourth match of the season, with the 31-year-old forward having scored two goals from seven attempts on-target.

Canberra sit fourth on the ladder with two wins, two losses and a draw, while Adelaide have endured a slow start to the season with four losses.

Stengel's absence has seen domestic players Hayley Taylor-Young and Ashlie Crofts play extended minutes, with the latter scoring on her starting debut in round three.

"We've obviously got an international strike force but also domestic players who can come in as well," Garriock said.

"We've got some really young and talented players that get an opportunity.

"As we saw, Ashlie scored on [her starting] debut, so she's prolific and Hayley is a threat as well. One door closes with injuries but this week we're going to see the opportunity for other players to play up front.

"They've played a good role and are talented forwards, especially of the future."

W-LEAGUE ROUND SIX

Sunday: Adelaide United v Canberra United in Adelaide, 4pm AEDT

Canberra United squad: 1.Annalee Grove, 2.Laura Hughes, 3.Kaleigh Kurtz, 4. Jessie Rasschaert, 5.Nikola Orgill (c), 6.Emma Stanbury, 7.Simone Charley, 8.Olivia Price, 10.Camila Pereira, 11.Elise Thorsnes, 12.Hayley Taylor-Young, 15. Ashlie Crofts, 16.Karly Roestbakken, 19.Leena Khamis, 20.Shamiran Khamis, 23. Lauren Keir *one to be omitted*