Il Nuovo Postiglione - Slipper out of retirement for Wallabies' Nations Championship campaign

Slipper, 37, retired from the international game last October but has been coaxed back after a standout season with the ACT Brumbies.

He is currently the third most-capped Test player on 151 and could surpass All Blacks great Sam Whitelock, who earned 153. Welsh lock Alun Wyn Jones is the all-time leader with 170 caps.

Fellow loosehead Angus Bell is also back in the frame following a season-long sabbatical with Ulster in Ireland.

Slipper's Brumbies teammates Declan Meredith and Lachlan Shaw, along with NSW Waratahs enforcer Miles Amatosero, were called up and are in line for debuts.

"There have been ongoing discussions amongst the coaches for a number of months and, as always, there are some very good players who have not been selected for this first international window," Schmidt said.

"We've settled on a group that we think will work hard and can perform well against three top-tier European teams with the added excitement of competing in the new Nations Championship for the first time."

Australia kick off the inaugural championship at home in July against Ireland, France and Italy in what will be Schmidt's final Tests before handing the reins to incoming head coach Les Kiss.

Several players return from injury absences, including scrum-half Tate McDermott and fullback Tom Wright.

Schmidt named Tom Hooper and fellow Exeter star Len Ikitau, who are playing in the English Premiership final this weekend.

Whether they are considered for the first Test against Ireland on July 4 in Sydney, given their lack of preparation time, remains to be seen.

Taniela Tupou is in a similar boat, given he is set to line up for Racing 92 in the semi-finals of France's Top 14.

Lock Lukhan Salakaia-Loto was a notable omission.

Among those not available were fellow lock Will Skelton who is out for the season with an Achilles injury and scrum-half Jake Gordon with a similar problem.

Forwards: Allan Alaalatoa, Miles Amatosero, Angus Bell, Charlie Cale, Josh Canham, Nick Champion De Crespigny, Tom Hooper, Fraser McReight, Josh Nasser, Zane Nonggorr, Brandon Paenga-Amosa, Billy Pollard, Aidan Ross, Lachlan Shaw, James Slipper, Carlo Tizzano, Taniela Tupou, Rob Valetini, Jeremy Williams, Harry Wilson

Backs: Jock Campbell, Filipo Daugunu, Ben Donaldson, Josh Flook, Carter Gordon, Len Ikitau, Max Jorgensen, Ryan Lonergan, Tate McDermott, Declan Meredith, Hunter Paisami, Dylan Pietsch, Harry Potter, Joseph-Aukuso Suaalii, Kalani Thomas, Corey Toole, Tom Wright

Australia fixtures:

Saturday, July 4: Australia v Ireland, Sydney

Saturday, July 11: Australia v France, Brisbane

Saturday, July 18: Australia v Italy, Perth

D.Campanella--INP