Josh Lewsey, Simon Shaw, Fraser Waters, Craig Dowd and Rob Howley for this game. Dowd joins Trevor Leota and Will Green in the front row with Shaw and Martin Purdy at lock. Jonny O'Connor, Worsley and Dallaglio make up the backrow.
The backline will see Mark Van Gisbergen at fullback with Lewsey and Voyce on the wings. Mark Denney starts at No.12 with Waters alongside him. Howley and Alex King start at 9 and 10 respectively.
Richard Birkett (Kidney) is still out injured, but the big lock is making steady progress and hopes to be back sometime next month. Injuries to Phil Greening (Foot) and Abbott (Ankle) see them missing the game.
Gatland said, "We are going to Perpignan to win. There are all sorts of permutations as to who could top Pool Six but the bottom line is we must win. Wednesday's training session was one of the hardest we've had at the club and the fitness staff got stuck into the boys.
"The next two games could determine where we finish both in Europe and in the Premiership. The boys know this and are preparing for a tough, physical two weeks".