Whitelock will start beside Brodie Retallick in a test for the 61st time.
Foster included prop Nepo Laulala at tighthead in place of Ofa Tuungafasi, who received a yellow card and produced an ineffective performance at scrums in the second test.
Veteran hooker Dane Coles was included on the reserves bench along with former New Zealand Warriors captain Roger Tuivasa-Sheck, who is in line for an All Blacks test debut in midfield.
Ireland, meanwhile, promoted New Zealand-born center Bundee Aki into their starting lineup in the only change to the XV that started in the second test.
Aki replaced the injured Garry Ringrose at second five in a new midfield partnership with Robbie Henshaw. Keith Earls moved into the squad to take Aki's place on the bench. Aki joins two other New Zealand-born players in the Ireland backline — halfback Jamison Gibson-Park and winger James Lowe.
Foster already is under pressure after the All Blacks' first-ever home loss to Ireland last weekend and that pressure likely would become insurmountable if his team slump to an unprecedented series defeat.
New Zealand Rugby might have to act to allay public concern about the form and direction of the All Blacks just over a year out from the World Cup.
Foster has maintained a positive outlook and mostly remained loyal to players involved in the second test. Nothing in his selection suggests a major change to the tactics which Ireland read and negated last weekend.
"It's tough having a loss but the tough weeks are often the most exciting," Foster said. "A series decider against a high-quality side is a great occasion for our growth as a team."
-AP
The teams:
All Blacks: Jordie Barrett, Will Jordan, Rieko Ioane, David Havili, Sevu Reece, Beauden Barrett, Aaron Smith, Ardie Savea, Sam Cane (captain), Scott Barrett, Sam Whitelock, Brodie Retallick, Nepo Laulala, Codie Taylor, George Bower.
Reserves: Dane Coles, Aidan Ross, Ofa Tuungafasi, Akira Ioane, Dalton Papalii, Folau Fakatava, Richie Mo'unga, Roger Tuivasa-Sheck.
Ireland: Hugo Keenan, Mack Hansen, Bundee Aki, Robbie Henshaw, James Lowe, Johnny Sexton (c), Jamison Gibson-Park; Caelan Doris, Josh van der Flier, Peter O'Mahony, James Ryan, Tadhg Beirne, Tadhg Furlong, Dan Sheehan, Andrew Porter.
Reserves: Rob Herring, Cian Healy, Finlay Bealham, Kieran Treadwell, Jack Conan, Conor Murray, Joey Carbery, Keith Earls.
Odds
All Blacks: $1.25
Ireland: $4.00
Draw: $21
History:
All Blacks tests at Sky Stadium (last 10):
2012 - All Blacks 21 Argentina
2013 - All Blacks 27 Australia 16
2014 - All Blacks 14 South Africa 10
2016 - All Blacks 36 Wales 22
2016 - All Blacks 29 Australia 9
2017 - All Blacks 21 British and Irish Lions 24
2018 - All Blacks 26 France 13
2018 - All Blacks 34 South Africa 36
2019 - All Blacks 16 South Africa 16
2020 - All Blacks 16 Australia 16
Catching the action:
The Herald will be live blogging the test, while radio commentary is running live on Newstalk ZB, Gold Sport and on iHeartRadio.
The match is screening on Sky Sport 1 and live streaming on Sky Sport Now. And you can hear the eminently sensible hot-takes of the Alternative Commentary Collective by tuning in to Sky Sport 9, Radio Hauraki or by following their iHeartRadio channel.