Scotland's current intercontinental voyage of discovery has broken new ground.

In more than a century of international rugby tours, until now there has never been one where the second tour and all that follows have so little to do with each other. But as you read this, most of the players involved in last night's match against Canada are returning home, with only a handful of hardy souls heading to Argentina to rendezvous with the group that have been training in secret back home for Tour II: Flying South.

The problem is there are few sequels that match or better their originals and in different ways Scotland are going to struggle on both the South American and the South African branches of the trip.

Of immediate concern is that the squad won't finish assembling until tomorrow and will have no more than a couple of training sessions before heading for Cordoba where they play Argentina on Friday night.

Fortunately, Argentine demands and politics may play into their hands. So far the Pumas have relied entirely on home-based players and while they include the likes of Gabriel Ascarate, the centre who was on the books at Glasgow at the start of the season, there are none of the big familiar names.

Originally, the plan was to hold the likes of Juan Martin Fernandez Lobbe back for the Rugby Championship, the Southern Hemisphere equivalent of the Six Nations, but results might pressure the coaches to think again. As things stand, however, something a long way from a full-strength Scotland side will be playing something a long way from a full-strength Argentina team. Bit of a cheek calling it a Test and awarding caps, really.

Not that the Scots can afford to shrug if off. For some individuals, it could be career defining, particularly since their rivals have had first bite at impressing Vern Cotter, the new head coach, and first impressions count.

Take, for example, Duncan Weir. At the end of the Six Nations, he was the man in possession of the Scotland fly-half position. His last-second drop goal to snatch a win over Italy had made it look as though he was set for a long run in the berth, only he didn't realise events were conspiring against him back at his own club, Glasgow Warriors.

There, Finn Russell had been getting himself noticed both as an inside centre and fly-half. One slightly sloppy performance from Weir in Munster and Russell was in, taking his chance with both hands and going on to claim the position for the RaboDirect PRO12 knock-out games - where Weir could not even make the 23 - and winning his first cap against the USA.

As things stand Russell is one of those who should be on a plane back to Scotland, leaving Weir in pole position to recapture his place over the next two games. The pressure is on, though. He has Tom Heathcote, newly-signed for Edinburgh and desperate to prove he is worth the hype that brought him into Scotland reckoning two years ago, alongside him and both know a swathe of supporters are ready to anoint Russell whether he is there or not.

It is a similar story for Ross Ford, who has been Scotland's first-choice hooker for the last six or seven years but suddenly finds himself facing competition on two fronts - from older players, with Scott Lawson showing better hooking and line-out skills and having gone back to being the number one No 2, while at the opposite end of the age range, there has been a sudden influx of young guns ready to oust the old brigade led by Pat MacArthur but with the likes of Kevin Bryce and Fraser Brown just behind.

It is the same all over the team. All the squad are based in Scotland at the moment, though Geoff Cross and Moray Low are heading to England once they get home. In many, or even most, cases the players with the pedigrees are the ones that have reaped the financial rewards of Exile contracts, so this is a rare chance to show that home-based does not mean second rate. Careers depend on this sequel measuring up.