Shingler has failed to recover from a foot injury to take his place in the squad whilst Beck has picked up a groin injury.
Former Wales Under 20 captain Navidi, who was part Wales’ RBS 6 Nations and Japan tour training squads, replaces Shingler.
Carmarthen born Warren, who made his international debut last summer against the Barbarians at the Millennium Stadium, has been training with the squad in recent weeks and comes in for Beck.
