* Carter back for now, Slade may return
* Sonny Bill Williams returns after two years of rugby league (Adds details paras 10-13)
WELLINGTON, Oct 20 (Reuters) - Injured flyhalf Dan Carter did enough to prove his fitness to New Zealand coach Steve Hansen and win a berth in the All Blacks squad for the northern hemisphere tour.
Carter, one of three flyhalves in the 34-man squad named on Monday, replaces Colin Slade, who kicked the game-winning conversion against Australia on Saturday.
Carter will go on tour for tests against the United States, England, Scotland and Wales despite having barely played this year and still trying to overcome the effects of a broken leg sustained in the Super Rugby final in August.
"He's been training without being able to play because he's had a bit of nerve damage to the leg he broke," Hansen told Fairfax Media in Christchurch of Carter's inclusion.
"He's getting better and better all the time and he's extremely confident of being able to play.
"He knows his body better than anybody and if he's confident, I'm confident."
While Hansen said Carter was confident of getting through unscathed, Slade's conversion of Malaki Fekitoa's 80th minute try that clinched a 29-28 victory over the Wallabies may not be his last act on the rugby field this year.
"We've spoken to Sladey about the DC situation," Hansen added. "We'll monitor DC this week and get an idea of where he's likely to be.
"If DC can't make this trip because of his leg then Colin Slade will come back in."
Carter's inclusion despite having barely played this year suggests he remains firmly in Hansen's 2015 World Cup plans despite a horrendous run of injuries since the 2011 tournament.
Widely considered the best flyhalf in world rugby, he is likely to be the starting pivot in England next year with Aaron Cruden and Beauden Barrett, who shared the starting role this season while Carter was on a six-month sabbatical then recovering from injury, in the backup roles.
Cruden was supplanted by Barrett as the starter for the latter part of the Rugby Championship after he was late for the team's assembly time for their flight to Argentina following a boozy night out and left at home by Hansen.
The 25-year-old Cruden was brought back into the squad for the third Bledisloe Cup match in Brisbane but not named in the matchday team with Barrett given the nod to start and Slade offering more versatility off the bench by being able to cover flyhalf, wing and fullback.
Code-swapping centre Sonny Bill Williams was included after having played less than a full game of rugby since his return to the 15-man code following two seasons with the Sydney Roosters in Australia's National Rugby League.
Williams had a successful stint in union that included a World Cup win with the All Blacks in 2011 and a Super Rugby title with the Waikato Chiefs.
However, with only five tests before next year's World Cup, Hansen was keen to have the bullocking player involved as quickly as possible.
Lock Luke Romano was a surprise inclusion after breaking his leg in Super Rugby and not playing for five months.
Hansen said his selection was to get him up to speed with the team's game plan and allow first-choice pairing Brodie Retallick and Sam Whitelock some down-time on tour.
"Luke hasn't played a lot of rugby due to injury over the last 18 months, so we thought it would be good to get him back into the All Black way," Hansen added.
The All Blacks face the U.S. in Chicago on Nov. 1 before they meet England, Scotland and Wales on successive weekends.
Backs - Israel Dagg, Ben Smith, Charles Piutau, Cory Jane, Julian Savea, Malakai Fekitoa, Conrad Smith, Sonny Bill Williams, Ryan Crotty, Dan Carter, Beauden Barrett, Aaron Cruden, Aaron Smith, TJ Perenara, Augustine Pulu.
Forwards - Kieran Read, Richie McCaw (captain), Sam Cane, Jerome Kaino, Liam Messam, Victor Vito, Patrick Tuipulotu, Brodie Retallick, Jeremy Thrush, Luke Romano, Sam Whitelock, Ben Franks, Owen Franks, Charlie Faumuina, Joe Moody, Wyatt Crockett, Dane Coles, Keven Mealamu, Nathan Harris. (Reporting by Greg Stutchbury; Editing by Ian Ransom/amlan Chakraborty)