The £25million striker missed the weekend draw with Blackburn after picking up a dead leg but it was hoped he would be fit for the trip to Austria, as City look to bounce back from poor Premier League results either side of the international break.
However, Adebayor was not in the 20-man squad that left Manchester airport on Wednesday afternoon, which left manager Roberto Mancini with just two orthodox strikers in Carols Tevez and Jo.
There was no Joleon Lescott either, although his absence was balanced by the inclusion of Wayne Bridge, who is set to make his first appearance of the season after recovering from the ankle injury he picked up during the summer tour of America.
Skipper Tevez was available despite a minor calf problem for a game City are expected to win given Salzburg's disappointing start to the season.
With Italian giants Juventus and Polish outfit Lech Poznan to meet as well, the Blues will not have it easy.
However, goalkeeper Joe Hart has signalled a determination to respond from recent disappointments as City launch another bid to end a trophy drought that dates back to 1976.
"It will not be easy, the place will be buzzing and Salzburg proved last year winning their title and their group in this competition that they are a decent side," he told the club's official website.
"We are determined to bounce back from the disappointment of dropping points at home, though I don't think we played badly at all against Blackburn.
"We have been solid defensively all season and that is important when you go away from home in any competition.
"We are in a very competitive group for qualification and in such circumstances getting off to the fastest of starts is important.
"We can't take anything for granted."
Man City (from): Hart, Given, Taylor, Zabaleta, Richards, K Toure, Kompany, Boyata, Bridge, Cunningham, De Jong, Vieira, Wright-Phillips, Y Toure, Silva, Barry, Milner, Johnson, Tevez, Jo.