WELCOME to international rugby Mr Cotter.

As coach of Clermont Auvergne, if he ran into injury problems that threatened his ability to field a team, he could always buy a player in; a medical joke, they called it in France. However, in only his second week in charge of Scotland, Cotter is facing his first major injury issue, with David Denton, the Edinburgh No.8, the latest to drop out and no chance for the coach to go shopping for replacements.

He has only the absolute minimum of four back rows for this Friday's match against Argentina in Cordoba and two of them are then being forced by their clubs to go home, leaving him with only two players for four berths in the final match against South Africa - unless he resorts to drafting in players from either the Sevens squad preparing for the Commonwealth Games or the Under 20s.

Denton had been named as one of the party that went straight from Scotland to Argentina, bypassing the North American leg of the tour. Had he made it, he would have been the only specialist No.8 in the group and would have been certain to play in both the Tests, in Cordoba and Port Elizabeth, the latter less than 50 miles from Kingswood, where he went to school and one he had particularly been looking forward to.

Even when he came off with concussion 27 minutes into Edinburgh's final RaboDirect Pro12 match against Leinster, there were no real fears over his involvement in the tour since was never scheduled to travel until six weeks after he sustained the damage. However, while the current concussion protocols can clear a player in six days, they are also open ended if there is any adverse reaction. The days when players, the medical staff and coaches tended to ignore the issue are long gone.

All of which is a rude education for Cotter on the major difference between club coaching and international coaching. With back rows dropping like flies — there were injuries before the tour and he lost three more back rows in a single match last Saturday, against Canada — he has to try to field a team.

Unless he gets really unlucky, he should be all right for Friday's match, when Kieran Low and Blair Cowan are both in line to add to their cap tallies - but the pair have to leave the tour after this match since they are both at London Irish and the English Premiership are refusing to release players for next week's match. That leaves only Chris Fusaro and Rob Harley as specialist back rows in the current squad allowed to travel on to Port Elizabeth.

Cotter's options are limited. He has an experienced No.8 in Richie Vernon training with the Sevens squad, but he has spent the last six months converting to play centre and has lost some of the bulk needed to play in the forwards. James Eddie and Roddy Grant are also with the Sevens squad and look more obvious replacements.

His other option is to look at the Under 20s, where Tommy Spinks from London Scottish is captain. There's also Jamie Ritchie, who has been earmarked as one for the future with an Edinburgh contract at only 18, while Magnus Bradbury is already a development player with Edinburgh. Aside from age and inexperience, however, they don't finish their Junior World Championship matches until Friday and after five games in three weeks, it is hard to see any being capable of adding a full senior Test to their programme.

In the short term, only six of the starting team against Canada are available to face Argentina and the sight of Peter Horne, the starting centre, on the sidelines having a muscle complaint treated cannot have improved his mood.

Both Horne and the medical staff expect the player to be available for Friday, but the way injuries have gone on the tour so far, he will be wary of too much optimism as the Test looms large.

Even with all the setbacks, though, the players see it as an opportunity to build on everything that has happened so far. "Every training session gives us a base, that game [against Canada] gave us our level and we have to step up," explained Harley. "I hope we will see that against Argentina.

"Every player is going to he hard on himself, as you analyse all the stuff but watching the last game, there are a lot of positives. The way we attacked looked dangerous, especially the driving maul, the last two games have shown times when we have set up chances, got it tight and got going for the line."