The Matildas are due to return to action in Sydney on Friday against one of their local rivals, in what should be key preparation for next year's home Asian Cup.
But some of their biggest names are already out of the picture for the pair of friendlies.
Katrina Gorry (ankle) withdrew ahead of the window while Ellie Carpenter (ankle) and Hayley Raso (thigh) were ruled out on Thursday through pre-existing injuries, and later sent back to their respective clubs.
Arnold suffered an arm injury in Matildas training this week and will miss at least Friday's game against the world No.19 at Allianz Stadium.
Football Australia (FA) confirmed she would continue to be monitored by the team's medical staff.
It is a disappointing setback for Arnold, who had been starting at club team Portland as she jostles with Teagan Micah to start for the Matildas.
Liverpool shotstopper Micah is poised to start on Friday and likely Monday's match in Newcastle, with Chloe Lincoln as deputy and Sally James third goalkeeper.
The games should be the final pair under interim coach Tom Sermanni, with FA keen to have Tony Gustavsson's permanent successor in place by mid-year.
Lyon coach Joe Montemurro is the clear front runner for the position, though he is contracted for next season.
FA Board member Heather Garriock, who is leading the recruitment process, has previously indicated top coaches being under contract has contributed to the delay, telling AAP in February: "the best coaches, they're obviously coaching."
Western United coach John Aloisi looms as a smoky, after leading a youth-filled team to second in the A-League Men.
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