Dewi Lake will captain Wales against South Africa at Twickenham on Saturday, with scrum-half Ellis Bevan to make his test debut in the clash, coach Warren Gatland announced on Tuesday.
Hooker Lake takes over the captaincy from Dayfdd Jenkins, who led the side in the Six Nations Championship earlier this year, but who, along with other players based at English or French clubs, is not available for the one-off game against the World Cup winners.
Tight-head prop Henry Thomas has been ruled out with a foot injury, with Keiron Assiratti starting in the front-row.
Harri O'Connor comes onto the bench in place of Assiratti for the clash against the world champions, with both teams fielding weakened sides as the fixture falls outside of the international window.
Wales have also called Bath wing Regan Grace into their wider squad of 38 players, with Keelan Giles released due to a groin injury.
Coach Warren Gatland will reduce the squad to 34 players next week ahead of a trip to Australia where they will play tests on July 6 and 13.
Jac Morgan was expected to skipper the side but has been released from the squad after failing to recover from a hamstring injury suffered in Ospreys' quarterfinal defeat at Munster in the United Rugby Championship on June 7 and will not go on Wales' tour of Australia next month.
Cardiff's Bevan takes over at scrum-half from Tomos Williams, who recently had ankle surgery.
There is also a first start for Dragons second rower Matthew Screech, who made a replacement appearance against Argentina three years ago, as Wales are severely hampered in the lock department with eight possible options out for Saturday's clash.
James Ratti from Ospreys was called up on Tuesday to cover both the second and back rows and immediately named among the substitutes. He is, therefore, expected to make his Wales debut from the bench, alongside Eddie James and Jacob Beetham.
James Botham -- who was called into the squad on Monday -- is named at openside flank while Taine Plumtree is on the blindside as he wins a third cap, having last featured for Wales against England at Twickenham in August last year.
Liam Williams starts on the wing in his first appearance since last year's World Cup in France.
"We have our backs to the wall a little bit this week, but we're really excited about the challenge on Saturday," Gatland said in a statement.
"The coaches and I have been very happy with the effort that's going in. There's a huge amount of potential in this group and the next five weeks will be extremely important for us in terms of wanting to develop this team."
Wales squad for match against South Africa
Team: 15-Cameron Winnett, 14-Liam Williams, 13-Owen Watkin, 12-Mason Grady, 11-Rio Dyer, 10-Sam Costelow, 9-Ellis Bevan, 8-Aaron Wainwright, 7-James Botham, 6-Taine Plumtree, 5-Ben Carter, 4-Matthew Screech, 3- Kieron Assiratti, 2-Dewi Lake (captain), 1-Gareth Thomas
Replacements: 16-Evan Lloyd, 17-Kemsley Mathias, 18-Harri O'Connor, 19-James Ratti, 20-Mackenzie Martin, 21-Gareth Davies, 22-Eddie James, 23-Jacob Beetham