With Dan Lydiate out injured after breaking an ankle playing for the Dragons earlier this season, Turnbull has been given the nod to wear the number six shirt.
Turnbull starts in the back row alongside captain Sam Warburton and Toby Faletau as Wales look to get their autumn campaign off to a winning start.
Following injuries to Lydiate and Ryan Jones, Wales’ interim coach Rob Howley has gone for Turnbull ahead of the likes of Rob McCusker and Aaron Shingler in the back row.
And the Scarlets man, who has played most of his rugby at openside so far this season, is delighted to have been given a chance to impress.
“It was a bit of a nervous spell but I’m so chuffed,” said Turnbull who admitted he spent a nervous evening before the team announcement at the cinema.
“It’s big boots to fill. Dan is a credit to himself in what he’s achieved in the last 18 months, being Six Nations player of the tournament. If I can replicate that form on Saturday I’ll be a happy man.
“Over the last couple of weeks I’ve got my head down and put the hard graft in. I’ve had a couple of near misses in the past so I’m hoping to take this opportunity with both hands.”
Although he has been playing most of his regional rugby at openside so far this season, Turnbull believes the move across the scrum won’t be a problem.
“At the Scarlets we like to play with no numbers on our backs, we each bring something different to the table but I’m happy to move back to six,” he added.
“It has been a position a few of the boys have been going for. It’s an opportunity now for someone to put their name on the jersey for the rest of the autumn internationals.”
Saturday’s clash with Argentina sees Turnbull again link up with Warburton, a partnership the two first enjoyed playing at junior and U20 level. And the Scarlet’s man knows the Wales pack will be in for a tough test against the South Americans on Saturday.
“Argentina have got a front five that will put them in decent positions,” said Turnbull.
“They’re very forward dominated but we’ve got to play at our own pace and at a level that suits us.”
