The 23-year-old - an important cog for Scarlets having made 20 Guinness PRO12 appearances last season - was called up to replace Lloyd Williams, who was sent home on Saturday with an ankle injury.
His Scarlets team-mate Rhys Patchell could also feature after being called up as an injury replacement for Gareth Anscombe, in what would be his first international appearance in three years.
However, 18-year-old Ospreys winger Keelan Giles is not involved in the squad, despite linking up with Gatland's men on Saturday after George North was ruled out of the tour.
Luke Charteris captains the team, which includes the likes of Scott Baldwin, Gareth Davies, Rhys Priestland and Scott Williams.
"Tuesday is a huge opportunity for these players, they have trained hard and are ready to get game time under their belts," said Gatland.
"Coming all the way to New Zealand, it was important we had a big enough squad for the three tests but also to provide game time for the players on tour and this match gives the players a chance to stake their claim for the final two tests against the All Blacks.
"We were hosted fantastically well by the people of Waikato in the 2011 RWC, so it's great to be back and to give something back to the region.
"The Chiefs are without a number of their All Blacks but still boost a strong side and from my playing days I know they will be right up for the fixture against a touring nation."
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Guinness PRO12 Scarlets News
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