Germany have a maximum 15 points from five qualifiers and another two victories against Austria and Azerbaijan on June 7 could see them all but through to next year's finals in Poland and Ukraine.
Coach Joachim Low, however, has fitness doubts over Sami Khedira while fellow midfielders Bastian Schweinsteiger, Christian Trasch and Sven Bender are definitely ruled out by injury.
Gomez finished as the Bundesliga's top scorer this season and also netted in Sunday's 2-1 friendly win over Uruguay.
"We have decided not to bring other players in because we trust the current squad," Loew said on Wednesday.
Austria have seven points from five games and coach Didi Constantini is playing one of his last cards as he bids to keep alive the fourth-placed team's slim hopes of reaching the finals.
"We are the clear outsiders but that also means we have nothing to lose," said Janko. "We want to anger our big brother and maybe it will be enough for a draw or even a sensation.
"We are in a position where only victories will do for us right now."
