Scotland will head to South Africa this summer seeking to identify a new species of player capable of winning regularly at Test level after nine uncapped players were named in the 31 tour party.

That represents close to a third of the personnel and while there remains a nucleus of old campaigners, Scott Johnson, who will be engaging in his last campaign as the team's head coach and his first as the sport's director of rugby, acknowledged it was something of a journey into the unknown.

"We acknowledged we were two years out from the World Cup; it was a Lions year so we lost a couple of players," he explained after naming a squad that included the nine newcomers in Steven Lawrie and Greig Tonks from Edinburgh, Pat MacArthur, Tim Swinson, Alex Dunbar, Peter Horne, Peter Murchie and Tommy Seymour from Glasgow Warriors and the Saracens winger Duncan Taylor.

"There are kids who have been performing pretty well but we are not sure if they can take the next step. This is an ideal opportunity to find out.

"It is important for the growth and depth of our squad. What will be more beneficial to us is to find out if the players can step up. It is really important we understand that. If there are a couple of guys who go through the roof and put their hand up that will be important. I don't really want to talk about the negatives but we want people to stand up and put pressure on others."

Perhaps the biggest surprise was the omission of Rob Harley, one of the most promising youngsters in the game who featured prominently in the RBS 6 Nations, while Nick De Luca and Max Evans, squad regulars in recent years, are also being left behind.

"It was hard on Rob but the fact is that it was the right balance and that is just what happens," said Johnson. "Some of the reasoning behind not bringing Max or Nick [was] because I know what they can do. If things were not going that great and they were standing there I might bring them in. I don't think that is what it is about. I need to find out about a couple of lads."

To that end, Johnson suggested that, while Scotland will naturally be looking to do as well as possible in what is an innovative tournament at this level of the game, the key is to strengthen the squad for the man who takes over from him as the permanent head coach.

"We are about performing, but this tour is about knowing where this squad is, where our depth of player base is," said Johnson. "If we get a couple of good quality players out of it then it will increase our depth significantly."