Frizell, 22, plays for St George-Illawarra and had been a doubt for the tournament.
Wales coach Iestyn Harris said: “I think we have a really strong team for the opening game. We’re going into it with confidence but we know that we’ll have a tough time against Italy especially after their win over England last week.
“I’m pleased that Tyson Frizell has overcome his injury. He, and of course all of the others, have worked hard to be here. We now can’t wait for Saturday to play in front of a packed house at the Millennium Stadium in Cardiff.”
Wales: Neil Budworth (Moranbah), Ross Divorty (York), Gil Dudson (Wigan), Jacob Emmitt (Salford), Ben Evans (Bradford), Rhys Evans (Warrington), Ben Flower (Wigan), Tyson Frizell (St George), Jordan James (Salford), Elliot Kear (Bradford), Craig Kopczak (Huddersfield), Rhodri Lloyd (Wigan), Peter Lupton (Workington), Larne Patrick (Huddersfield), Matt Seamark (Wynnum Manly), Anthony Walker (St Helens), Ian Webster (Central Queensland), Lloyd White (Widnes), Rhys Williams (Warrington).
Italy: Anthony Minichiello (Sydney), Joshua Mantellato (Newcastle), James Tedesco (Wests), Aiden Guerra (Sydney), Chris Centrone (North Sydney), Ben Falcone (Souths Logan), Ryan Ghietti (Northern Pride), Anthony Laffranchi (St Helens), Dean Parata (Parramatta), Paul Vaughan (Canberra), Mark Minichiello (Gold Coast), Cameron Ciraldo (Penrith), Joel Riethmuller (North Queensland). Interchanges (from): Sam Gardel (Souths Logan), Ryan Tramonte (Windsor), Brendan Santi (Wests), Raymond Nasso (Avignon), Tim Maccan (Tweed Heads), Gavin Hiscox (Central Queensland)