The England U19 international will replace Jonny Tattersall for the County Championship fixture at Sophia Gardens.
Duke, who turns 20 in September, has been handed his chance after some impressive displays at second-team level, including fifties in recent games in Bristol and Guildford.
Tattersall, 26, has been keeping well but has made 101 runs in eight Championship innings, prompting Yorkshire to make the change.
Tattersall will look to rediscover his form in the second XI and he made a solid start yesterday with an unbeaten 45 against Lancashire at Scarborough before rain intervened.
Dom Bess is set to replace him at No 6 in Cardiff, with Duke likely to feature at No 7.
David Willey also returns to the squad after sitting out last week’s match against Kent, while Joe Root plays his final Championship game before the international programme.
The game is being shown live on Sky Sports, which suddenly has air-time to fill following the postponement of the Indian Premier League, with Yorkshire’s match against Lancashire at Old Trafford (May 27-30) also to be shown live prior to the New Zealand Test series that begins on June 2.
Despite the presence of the television cameras this week, plus a commentary team that includes former England captains Michael Atherton and Nasser Hussain, Yorkshire are confident that Duke will not be fazed by the occasion as the second-placed White Rose look to maintain their unbeaten start in Group Three after three wins and two draws at the halfway stage.
Martyn Moxon, the Yorkshire director of cricket, said: “Harry is a real competitor, a real scrapper and a battler, and he’ll thrive on that (the game being televised). He’s the kind of character who will relish the stage, and it’s a great chance for him as a talented young player.
“Harry has definitely got a bit of something about him and is a typical wicketkeeper, if you can call it that. He’s someone with a huge desire to be the best he can be, and he’s definitely got the talent, there’s no doubt about that.”
Duke, who comes from Wakefield, and has worked his way up through the Yorkshire ranks, edged out Ben Birkhead, another young keeper Yorkshire rate highly.
Tattersall has been first-choice keeper since 2018 in Jonny Bairstow’s absence with England, and he averages 25 from 41 Championship innings, with five half-centuries.
“Tatts has found it quite tough so far this season with the bat,” said Moxon, “and we’re hoping that he can play a couple of second-team games and regain some form and confidence there. It’s just a case of him hopefully getting a big score behind him and getting that confidence back.
“It’s certainly not been through a lack of effort, because he’s worked tirelessly in the nets but it’s just not been happening for him of late. But that happens with anyone – people have a dip in form – and there’s no shame in playing a couple of second-team games and I’m sure that Tatts will bounce back.”
Despite averaging fractionally less than Tattersall this year, Yorkshire will keep faith with Tom Kohler-Cadmore, a proven run-scorer in all formats.
Although the 26-year-old made only 14 in his one innings against Kent last week, Moxon saw signs of a player on the cusp of a big score.
“There’s signs that hopefully that will come soon,” he said. “Hopefully Tom will break that barrier this week, and he’s fully aware of what he’s got to do and is working very hard.
“Tom played really well in the last game, I thought, in challenging conditions against Kent.
“He left the ball well, he got his feet moving well, then he just made an error and dragged one on.”
Yorkshire are targeting improvement in their batting per se, with results having masked some underwhelming totals.
Their battling qualities have been pulling them through – as in narrow wins against Sussex and Northants.
“We’ve been getting results, which I think is testament really to the fighting spirit within the group and the desire to do well,” added Moxon.
“We’ve fought back from some tricky positions really well, so we’ve got to commend that. But, by the same token, we know there’s a lot of room for improvement, particularly in terms of the top-six batting.
“But you look down the batting order and everybody is capable of scoring hundreds; it’s just a matter of it all coming together and, when we do that, we’re going to be an even better team.”
Yorkshire squad: Ballance, Bess, Brook, Coad, Duke, Kohler-Cadmore, Lyth, Olivier, Patterson (capt), Root, Thompson, Willey.
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