England have already sewn up the series with thumping victories in Christchurch and Wellington, leaving many questions over the make-up of the Black Caps team and their tactics.
Left-armer Santner has not played since taking 13 wickets in Pune in late October to help New Zealand to a remarkable 3-0 sweep of India, and his inclusion on Saturday will depend on the condition of the wicket.
"We're actually going to wait till tomorrow just to have a final look at that wicket. Obviously, conditions can be slightly different here," skipper Tom Latham told reporters in Hamilton on Friday.
"Will Young will come into the team and he'll open up with me. It's a great opportunity for Youngy, who on recent form has obviously played really nicely and has deserved this opportunity."
Young, who was named player of the series as a stand-in for Kane Williamson in India, gets his chance with regular opener Devon Conway remaining at home for the birth of his first child.
If Santner does come into the side at the expense of one of the four seamers who played the first two Tests, Latham made clear it would not be Tim Southee who makes way.
The 36-year-old right-arm swing bowler, who handed the captaincy over to Latham in early October, will bring down the curtain on his 16-year Test career in his 107th and final match at his home ground.
"It's a great occasion for Tim, last Test match ... Tim's looking forward to it. We're all looking forward to it," Latham said.
"He's going to be remembered as one of the greats of our game. The numbers back things up around that, but internally, the leader he is, the legacy that he's going to leave from a bowling point of view, he's certainly going to go down as one of the greats."
New Zealand cricket fans have turned out in big numbers for what has been a disappointing series, and Latham said the players hoped to give them something to cheer about in Hamilton.
"Obviously, we really appreciate the support," he said.
"We know we haven't played to our potential over the last couple of games, but hopefully we can put on a good showing for the fans."Â
