Guildford, the 20-year-old from Hawke's Bay, will wear the No 11 jersey vacated by Sitiveni Sivivatu who sits out a one-match ban for a dangerous tackle during the All Blacks' 32-19 win over the Wallabies in Tokyo.
The other backline change sees halfback Brendon Leonard swap with Jimmy Cowan, while in the forwards one-test prop Wyatt Crockett replaces the suspended Tony Woodcock, Eaton replaces Tom Donnelly, flanker Jerome Kaino replaces Adam Thomson and Kieran Read reclaims the No 8 jersey from Rodney So'oialo who missed the squad altogether.
On the bench, Otago fullback Ben Smith was named ahead of the injured Tamati Ellison (calf) for a potential test debut, while prop Owen Franks came in for John Afoa.
Star pivot Dan Carter was named at No 10 for the Millennium Stadium test despite taking no part in the team run at the Ospreys training ground at Neath today due to a bruised calf muscle.
Stephen Donald trained at first five-eighth in a rain-lashed session, but it was always planned for Carter to rest today as he sits just 15 points short of Andrew Mehrtens' All Blacks test pointscoring record of 967.
Lock Brad Thorn also suffered a knock at training and sat out the latter part of the session, but was still expected to start.
The All Blacks coaching trio were true to their word about giving most players a chance to impress on this six-match tour with a view to the 2011 World Cup.
Guildford was the predictable replacement for Sivivatu after he was summoned to the bench in Tokyo but wasn't required for his test debut.
The star of the New Zealand Under-20 side forced his way into the squad with a 13-try haul for Hawke's Bay in the Air NZ Cup and had continued to impress since joining the All Blacks squad.
"He's trained like a guy who's been there forever," assistant coach Steve Hansen said this week.
Eaton's selection for his 15th test was perhaps the biggest talking point, with Anthony Boric having appeared first cab off the rank in the locking merry-go-round.
The Taranaki lock, who debuted against Ireland on the 2005 grand slam tour, last started a test in August 2007 against the Wallabies in Auckland. His four tests this year were off the bench, including a brief appearance in Tokyo.
Leonard also gets his chance after a frustrating season where Cowan established himself as the first choice halfback.
The speedy Waikato No 9 started just two tests this year, against Italy and South Africa.
In the loose forwards, Read and Kaino wrested back their starting spots after missing out in close selection calls in Tokyo.
Read, the form No 8 this season, was expected to return while Kaino continued his tight selection battle with Thomson who was impressive in Tokyo and contributed to a solid lineout effort.
Crockett was a predictable replacement at loosehead prop, having made his debut against Italy in June then waited patiently in Woodcock's shadow until he copped a one-match ban for striking on Saturday.
Assistant coach Wayne Smith flagged the changes yesterday, making it clear this was a trial for the next two years.
"Part of the idea of this tour was to put heat on people, make it competitive and make sure players understood they were playing for their futures," Smith said.
"To do that you've got to give people games as well."
Mils Muliaina, Cory Jane, Conrad Smith, Ma'a Nonu, Zac Guildford, Dan Carter, Brendon Leonard, Kieran Read, Richie McCaw (captain), Jerome Kaino, Jason Eaton, Brad Thorn, Neemia Tialata, Andrew Hore, Wyatt Crockett.
Reserves: Corey Flynn, Owen Franks, Tom Donnelly, Adam Thomson, Jimmy Cowan, Stephen Donald, Ben Smith.
