FFA says Ryan, the first choice gloveman at the last two World Cups, has been given the October FIFA window off to help manage an unspecified minor injury, also ruling him out of this week's training camp in the United Arab Emirates.

It opens the door for Ryan's 2018 World Cup deputies Danny Vukovic and Brad Jones or Mitchell Langerak to start in goal against Kuwait at the Al Kuwait Sports Club Stadium on Monday (Tuesday AEDT).

Ryan kept a clean sheet in Brighton & Hove Albion's 1-0 Premier League win over West Ham on Friday but Arnold said it was best for him not to make the trip.

"Mathew's managing a minor injury which hasn't prevented him from playing or performing for Brighton so far this Premier League season," said Arnold, who mentored Ryan as a teenager at the Central Coast Mariners.

"He could have travelled to the Middle East, trained with us, and played against Kuwait, but for this window we believe it is best that he remains in Brighton and returns to full fitness with his club.

"We will have three very good goalkeepers with us this camp in Danny Vukovic, Brad Jones, and Mitchell Langerak.

"The time in the UAE and Kuwait will provide a great opportunity for each of these goalkeepers to show their best as next year's AFC Asian Cup draws nearer," he said.

Australian Associated Press