Duncan Weir comes in to partner Henry Pyrgos at half-back, while Peter Horne returns to the side at inside centre. Alex Dunbar keeps his spot at outside-centre, with Peter Murchie taking up the full-back slot.
Sean Maitland returns in place of Tommy Seymour, with DTH van der Merwe on the opposite wing. Tom Ryder starts alongside Al Kellock in the second row and James Eddie will start in the back row after Ryan Wilson suffered a shoulder injury in the win over Treviso.
Warriors will have a squad of just 22 due to a number of prop options being unavailable for the game.
Ofa Fainga'anuku, Mike Cusack and George Hunter are all injured, while Jon Welsh and Ed Kalman have not been available since the summer and were not included in the Heineken Cup squad, leaving Gordon Reid the only other fit and eligible prop available.
Following extensive discussions between the club and the competition organisers, the ERC confirmed that tournament rules would not allow another front row to be added to the list of eligible players.
Townsend said: "We're in a situation which we have never experienced before in the Heineken Cup.
"We've used all our options in terms of nominating additional players for the tournament so, even though German Araoz is fit and ready to play, the rules of the competition mean we can't bring in another player.
"It's unfortunate to have so many props out and that means, by tournament regulations, we have to go into the game a man down."