Having played against the Italians in the Six Nations, Bradley Davies and John Yapp return to Blues duty on the bench.
Martyn Williams has failed to recover from and injury to his foot sustained playing for Wales against Ireland last Saturday.
The Blues are unbeaten in their last four games in all competitions and reached the semi final following wins over the Sale Sharks, Leicester Tiger and Bath.
Cardiff Blues v Northampton Saints
EDF Energy Cup Semi-Final, Ricoh Arena, Coventry Saturday 28 March 5.15pm kick off
15 Ben Blair 14 Leigh Halfpenny 13 Tom Shanklin 12 Jamie Roberts 11 Tom James 10 Nicky Robinson 9 Jason Spice 1 Gethin Jenkins 2 Gareth Williams 3 Taufa'ao Filise 4 Deiniol Jones 5 Paul Tito (C) 6 Maama Molitika 7 Robin Sowden Taylor 8 Xavier Rush
Replacements 16 John Yapp - Fr 17 T Rhys Thomas - Fr 18 Bradley Davies 19 Scott Morgan 20 Richie Rees 21 Ceri Sweeney 22 Jamie Robinson