Leeds midfielder Paul Green replaces Glenn Whelan, who picked up a hamstring injury in the 2-1 defeat to Sweden, while Norwich's Anthony Pilkington comes in for James McClean on the left side of midfield.
Pilkington came on as a late substitute on Friday but will now make his first start for Trapattoni's side in Vienna.
Jon Walters (ankle) and Shane Long (dead leg) retain their places in the starting line-up after shaking off injuries.
The Republic must beat Austria and then win at group leaders Germany to keep their hopes of reaching next summer's finals alive.
But Trapattoni has already indicated that he expects to lose his job after this campaign.
Republic team to face Austria: Forde, Coleman, Dunne, O'Shea, Wilson, Walters, Green, McCarthy, Pilkington, Keane, Long.
Popularpete, though you're likely trolling, had a look at the players who've been playing for England lately, at senior and underage levels? Zaha (Ivory Coast), Sterling (Jamaica), Chalobah (Sierra Leone), Beharino (Burundi), Bigirimana (Burundi) and Ameobi (Nigeria), all born outside of England, not to mention the likes of Jenkinson (Finland), Osman (Turkey), Townsend (Cyprus, Jamaica), Barkley (Nigeria), Shelvey (Ireland), Cahill (Ireland), Welbeck (Ghana), Young (Jamaica), Cole (Barbados), Defoe (St. Lucia, Dominica), and Jagielka (Poland), and many, many others of mixed nationality who have played for England recently, some of whom have (and I'm speculating, but I know I'm right) been capped as early as possible by Hodgson solely to claim them for England lest they be needed in the future (namely Jenkinson, Shelvey, Sterling, Barkley, Zaha). So, you know, next time you're trolling, you probably shouldn't make it so that potential rebuttals are so satisfying.- MeMcMe