Michael Hooper, Australia, 21, 9 caps: Recently signed by New South Wales Waratahs, Hooper, who was named player of the tournament at the junior world championship in 2011, has made a phenomenal start to his senior Australia career since his debut in June. Technically, the understudy to the injured David Pocock, but pushing the incumbent openside hard for his placePhotograph: Chris Hyde/Getty ImagesPaddy Ryan, Australia, 24, uncapped: Despite his call up to the Australia squad in the summer, Ryan is still looking for his first cap. The prop has earned his place in the side after an impressive string of performances for NSW in Super RugbyPhotograph: Mark Nolan/Getty ImagesHenry Pyrgos, Scotland, 23, uncapped: With Lions star Chris Cusiter injured, scrum-half Henry Pyrgos, who joined Glasgow Warriors from Loughborough University in 2010, starts on the bench against New Zealand and will hope to make his debut. Qualifies through his Scottish-born motherPhotograph: Stu Forster/Getty ImagesAaron Jarvis, Wales, 26, uncapped: Ospreys prop Adam Jarvis has been named in the starting line-up for Saturday’s game against Argentina. The English born player has been in excellent form this season and will have a big test to fill the boots of the injured Lions prop Adam JonesPhotograph: David Rogers/Getty ImagesTawera Kerr-Barlow, New Zealand, 22, uncapped: Promising youngster Kerr-Barlow has been selected in a full strength New Zealand squad, the scrum-half earning a chance to win his first cap under Steve Hansen, who described Kerr-Barlow as “an exciting player”Photograph: Hagen Hopkins/Getty ImagesNick Cummins, Australia, 25, 2 caps: Winger Cummins is known for his aggressive style of play, comparing himself to the African “honey-badger” and modelling his attitude on its attributes. Yes, really. “The main reason it inspired me was that it’s documented that a honey badger killed a male lion in a one-on-one battle.” Right. Photograph: DAN PELED/EPADane Coles, New Zealand, 25, uncapped: Coles is the only other uncapped player to make it into Hansen’s squad. The hooker is keen to gain some experience on tour, describing his call up as “overwhelming”. Superb in the loose, has been likened by his Hurricanes coach, Mark Hammett, to the former Ireland hooker Keith WoodPhotograph: Hannah Johnston/Getty ImagesTom Youngs, England, 25, uncapped: Elder brother of scrum-half Ben, and son of former England scrum-half Nick, Tom is a centre-turned hooker who only got his first start for Leicester Tigers this season. Did produce several strong performances in the midweek games during England’s tour of South Africa this summer, but is still learning his craftPhotograph: David Rogers/Getty ImagesMako Vunipola, England, 21, uncapped: Promoted to the England senior team after impressive performances for the U18s and U20s, the Saracens’ loosehead will start on the bench against Fiji. New Zealand-born but with Tongan heritage (father, grandfather and six uncles all played for Tonga) Vunipola grew up in Wales after his father moved their to play for Pontypool. Graham Rowntree has said of him: “He’s a dynamic ball carrier but loves a scrum.”Photograph: Frances Leader/Action ImagesTim Visser, Scotland, 25, 2 caps: Andy Robinson must have been delighted when the Pro12’s top try scorer for the past three seasons, finally became eligible to play for Scotland. Visser, who was born in the Netherlands, is expected to play a key role in the autumn internationalsPhotograph: Lynne Cameron/PABrice Dulin, France, 22, 2 caps: The Castres Olympique full-back made his debut for France against Argentina in June. The highly rated player is a new signing, having been poached from over-achievers Agen. A former French champion at Basque pelota, he had to quit and turn to rugby following injury Photograph: Raymond Roig/AFP/Getty ImagesPhotograph: Raymond Roig/Action imagesMichael Bent Ireland, 26, uncapped: The New Zealand-born prop, Taranaki player of the year, and a former Super 15 player for the Hurricanes has been drafted into the Ireland squad after less than two weeks in the country. Bent, 26, qualifies through his maternal grandmother and recently signed for Pro12 club Leinster – although is yet to play for themPhotograph: Hagen Hopkins/Getty ImagesEben Etzebeth, South Africa, 21, 8 caps: A rapid rise to the Springboks side in 2012, playing his first game for the Stormers in the Super 15 in February and winning his first cap in the series against England in the summer. Dynamic and physicalPhotograph: David Rogers/Getty ImagesMaxime Machenaud, France, 23, 1 cap: A confirmed starter for Saturday’s game against Australia, scrum-half Machenaud will make his second appearance following his call up for France’s summer tour of Argentina. Flattened his rival for the No9 jersey, Morgan Parra, in a Top 14 match earlier this seasonPhotograph: Christophe Ena/APJulian Savea New Zealand, 23, 5 caps: Touted as the next Jonah Lomu, so no pressure there. The 2010 IRB junior player of the year scored three tries on his debut against Ireland at Eden Park in June and has six in total from his five appearancesPhotograph: John Cowpland/APNicolas Sanchez, Argentina, 24, 5 caps: A former tennis player, the 24-year-old centre moved to Bordeaux-Begles in the middle of last year and has been preferred at fly-half recently to one of Argentina’s most exciting players of recent years, Juan Martín HernandezPhotograph: AFP/Getty Images