LONDON, July 12 : England have called up Raffi Quirke as the replacement for injured scrum-half Alex Mitchell for Saturday's Nations Championship clash against Argentina in Santiago del Estero.The Sale Sharks scrum-half replaced Mitchell in this year's Six Nations squad when Mitchell also had a hamstring injury. The injury flared up again on Saturday after Mitchell came on for Jack van Poortvliet in the 73-8 thrashing of Fiji in Liverpool.Mitchell lasted nine minutes before limping off and was quickly ruled out of the trip to Argentina.Quirke, 24, won his two caps off the bench in 2021 tests against Australia and South Africa.Van Poortvliet and Bath's Ben Spencer are the two scrum-halves in the squad for England’s third game in the new competition. They lost to South Africa in their openin