Scotland have lost Ryan Grant to the British and Irish Lions but coach Scott Johnson is keen to see what Alasdair Dickinson has to offer as he steps into the front row to tackle Samoa.

Prop Grant's sudden promotion to the Lions ranks forced Scotland into a late shuffle of their squad for tomorrow's opener to the four-team tournament in South Africa, that also features the hosts and Italy.

Dickinson, who is moving from Sale to Edinburgh this summer, benefits, while Glasgow prop Moray Low is handed a place on the bench.

Jon Welsh, who even interim head coach Johnson admitted was unlucky to have missed the original selection for the tour, will be flying to South Africa over the weekend to join the rest of the squad as Grant's replacement.

So while Johnson was excited by Grant's call-up by the Lions, he is relishing the chance to see Dickinson in action. The prop has been injured for most of the season Johnson has been involved with Scottish rugby and the 29-year-old has not started a Test since the second of the warm-up games before the 2011 World Cup.

"From what I have seen, he is a quality athlete and, for his position. possesses a skillset that you don't see very often around the game," said Johnson.

"He can compete with anyone athletically and I am quite excited to see what he can bring. I keep coming back to the point that I want us to be competitive in all positions and hopefully that puts pressure on everyone.

"Ryan, Dicko [Dickinson] and Moray [Low] will all become better players if they are all fighting and vying for their positions. It is a great opportunity for him."

The changes created a last-moment level of uncertainty as Scotland prepared to take on Samoa. They may never have lost to tomorrow's opponents but both the last two games have been won only in the dying seconds, so there was no shortage of respect in the Scottish camp as they finished their preparations for the match.

The tournament is being played under the bonus-point system that is common in tournaments across the world. That means not only do Scotland need to win but, to give themselves a good chance of reaching the final in a fortnight, they almost certainly need to prevent Samoa picking up a losing bonus point as well.

Not that Johnson is worrying too much about that level of forward planning. As far as he is concerned, the important thing is to get the victory while blooding as many new players as he can.

"I keep saying that at the end of this, we need greater depth in our squad and we need to know the standard of our players and this is a perfect opportunity to see that," he said.

"We have viewed the tour as producing certain things but all sides are viewing it as a development phase. Teams like South Africa are probably preparing for bigger championships. Everything is different to the World Cup so we cannot look that far in front, we have to look at why we are trying to do things."

For Scotland the challenge is to show that they can lose a handful of their top players and still be competitive. Johnson has said that by the Rugby World Cup in a little more than two years he needs to have a squad where all 30 are viable candidates for starting positions.

That is why he has elected to leave some internationals with proven pedigrees behind and sent out a side with three uncapped players, two more making only their second appearances and a number of experiments. He has another three uncapped players on the bench with Peter Horne, the Glasgow centre, covering fly-half.

The idea, Johnson explained, is that with Ruaridh Jackson and Duncan Weir already capped, Tom Heathcote making his first start and Horne on standby, they should emerge from the tournament with four challengers for the pivotal position in the team - a position that has been a problem for Scotland for more than a decade.

Samoa have brought back the likes of Alesana Tuilangi, the former Leicester wing now in Japan, but do not have Kahn Fotuali'i, the Ospreys scrum-half, or Maurie Fa'asavalu, the Harlequins flanker, in their side.

A largely second-string version of the team was thrashed by the South African Lions franchise last week, but nobody sees that as a taste of the game to come.

Scotland are prepared for a huge physical tussle, with players hurtling into the tackles, and believe they have what it takes to come through it.

Scotland: G Tonks; S Lamont, A Dunbar, M Scott, T Visser; T Heathcote, G Laidlaw; A Dickinson, P MacArthur, E Murray, G Gilchrist, A Kellock, A Strokosch, K Brown, J Beattie.

Replacements: S Lawrie, M Low, G Cross, J Hamilton, R Wilson, H Pyrgos, P Horne, D Taylor.