The stalwart midfielder, who missed the Confederations Cup and the last World Cup qualifiers against Japan and Thailand, was named in a preliminary squad last week but omitted from the final 23-man list released on Wednesday.
Australia coach Ange Postecoglou has made five changes to the squad that lost to Japan and beat Thailand, with Israel-based striker Nikita Rukavytsya set to line up for the first time since 2014 in next week's away leg in Malacca, Malaysia.
Syria have been forced to play their 'home' qualifiers away from the war-torn Middle East nation due to security concerns.
The other four promoted, were defenders Aziz Behich, Matthew Jurman and Josh Risdon, and Netherlands-based midfielder Craig Goodwin.
Striker Jamie Maclaren and defenders Ryan McGowan and Alex Gersbach are among the seven to drop out of the preliminary 30-man squad.
Australia misfired in a 2-0 loss to Japan in Saitama and needed a late goal to spare their blushes against a lightly regarded Thailand in a 2-1 Melbourne win but Postecoglou denied his overhauled squad was a response to those performances.
"We're constantly looking at and assessing players," he told a media conference in Sydney on Wednesday.
"This is no different, it's not a reaction to anything other than continuing our -- my philosophy of making sure we're continually seeking and trying to improve.
"A couple of the players come in because they've been on the fringes for a while. We want to have a look at them."
The 30-year-old Rukavytsya's selection, however, would appear to underline enduring concerns about the side's finishing after they fired 45 shots against Thailand for the return of two goals.
He joins strikers Tomi Juric and the veteran Tim Cahill in the squad but Postecoglou will hope Germany-based midfielders Mathew Leckie and Robbie Kruse can bring their goal-scoring form at club level to Malaysia.
The teams return to Australia for the second leg at Sydney's Olympic Stadium on Oct. 10, with the winners of the two-leg playoff advancing to meet the fourth-placed side from the North and Central America qualifiers.
The winners of that intercontinental playoff secure a berth in the 32-team field for next year's World Cup finals in Russia.
Postecoglou is likely to hand the captain's armband to seasoned midfielder Mark Milligan or possibly Cahill if he starts in Malacca.
Squad:
Goalkeepers - Mat Ryan, Mitch Langerak, Danny Vukovic
Defenders - Aziz Behich, Milos Degenek, Mathew Jurman, Josh Risdon, Trent Sainsbury, Brad Smith, Bailey Wright.
Midfielders - Mustafa Amini, Craig Goodwin, Jackson Irvine, Robbie Kruse, Mathew Leckie, Massimo Luongo, Mark Milligan, Aaron Mooy, Tom Rogic, James Troisi.
Forwards - Tim Cahill, Tomi Juric, Nikita Rukavytsya.
(Reporting by Ian Ransom in Melbourne; Editing by Peter Rutherford/John O'Brien)
