Wales coach Mike Ruddock has picked teenager Chris Czekaj to make his Wales debut against Canada on Saturday.
The 19-year-old plays his first Test game at the York Stadium in Toronto after just two senior matches for Cardiff Blues.
He made his regional bow in the Celtic League match against Ulster on April 8 and also played against The Borders.
Czekaj scored five tries for Wales Under-21 last season in their triumphant Grand Slam campaign, his Under-21 team-mate and fly-half Matthew Jones on the bench for Mark Taylor's team against the Canucks.
Ruddock has made four changes to the starting line-up who beat the USA Eagles 77-3 in Hartford, Connecticut, last Saturday.
Czekaj comes in for the injured Craig Morgan on the wing, with Rhys Thomas taking over from Matthew Rees at hooker, Ben Broster from Adam Jones at tight-head prop and Robert Sidoli for Brent Cockbain in the second row.
"We brought Chris on the tour to see how he would respond to the squad environment and we are very pleased," said Ruddock.
"He has had a great season with the under-21s and has broken into the Blues side. He has impressed and has made enough progress for us to be very comfortable with him starting a Test.
"He is a natural left-sided player and we are looking for cover in that role for Shane Williams. Craig Morgan did well last week but we always wanted to have a look at both players during the tour. It means we will hopefully have at least three options there next season.
"With regards to the tight-head position, Ben did very well when he came on last week. The scrum continued to dominate while he was also very active in the loose with the ball in hand and he made some excellent tackles.
"Adam has had a great season for Wales and, very much like Brent Cockbain, is a mainstay of the pack. But this tour is finding out about different players and combinations as much as it is about winning both Tests.
"Rhys also impressed when he came on last week after Matthew's good work so we want to give him some more game time. Again, as with the left wing position, we are keen to build up some extra options in this area ready for a massive season coming up.
"Robert is back having got himself right after the Blues' important European Cup qualification match. Robert was a crucial part of our Six Nations campaign as line-out captain and there is an important role for him in this game with a lot of young forwards in the side.
"I expect Canada to be a lot better organised than the USA. They have had more time to recover after returning from Japan and they will benefit from the return of a number of European-based players and the assistance of Jonathan Humphries and the Tait brothers. This morning we looked at Canada's recent matches in fine detail in a video session.
"We have five changes on the bench which should mean that everyone on the tour will have played a part in at least one match which is great for us to gain knowledge of the players in a Test environment."
England flanker James Haskell insists he will be pushing as hard as possible to be back from a toe injury in time to make his case for a spot in Eddie Jones' side looking to defend their RBS 6 Nations title next year.