The fear of being outmuscled by South Africa may have added an extra dimension to the puzzles to be solved by Scotland's selectors ahead of Saturday's EMC Test at Murrayfield.

The way Scotland stood up physically to the world's leading side on Sunday offered encouragement but they know they face a very different type of challenge this weekend.

At least one change to the team is enforced and, in the past, John Barclay would have naturally replaced Ross Rennie, both being opensides. However, the reshuffle required on Saturday allowed the imposing Dave Denton lengthy time on the field alongside Kelly Brown and Al Strokosch, and the sheer physicality of that trio is a tempting combination.

Barclay is a relatively rare Scottish player in that he carries the natural bearing of a leader, having captained teams at every level short of Test rugby, which brings another element to the discussion. All the moreso when the ongoing debate over the second row is taken into account.

Even if the contest as to who should accompany the automatic choice that is Richie Gray was not as close in playing terms as it clearly is, a strong case could be made for Al Kellock on the basis of the authority he brings to proceedings.

Once again on Sunday, just as when he got his only starts of 2012 in the summer in the three Tests which were all won, Kellock was noticeably barking instructions the moment he took the field and while Brown has the full respect of his team-mates, that additional thinking capacity has to have been something he welcomed.

Our accompanying statistics also make fascinating reading when it comes to the debate between Kellock and the brawnier Jim Hamilton. The latter has impressed head coach Andy Robinson with his performances for Gloucester. However, for all that the English Premiership may be a more physical league, it is also a rather less dynamic one than the RaboDirect Pro12 which perhaps prepares players better for the speed of thought required at Test level.

Nor do those statistics which, standing alone with a winning record, show Kellock head and shoulders above any other established member of the current squad in terms of his success rate as a member of Scotland's starting XV, with Hamilton at the bottom of the 10 players who have started 20 or more Tests.

Further examination shows they have a 50% record on the surprisingly few occasions they have been paired considering they made their respective first starts in 2006, Kellock in a win against England, and 2007, Hamilton in a defeat to the same opponents, while Gray made his debut just two years ago.

Beyond that, four of Kellock's wins have come against teams ranked below Scotland to three for Hamilton, who can count two World Cup warm-up matches on his list of wins, compared with just one for his rival.

Perhaps most interesting of all is that Kellock has two wins to his name from five starts against the Southern Hemisphere big three while Hamilton is yet to get off the mark on that statistic, while Kellock has won six Six Nations matches, twice as many as Hamilton.

Those statistics are, of course, objective facts whereas a degree of subjectivity must always come into selection and it may be that a special case can be made for this particular match on the basis that, as when comparing the English Premiership with the RaboDirect Pro12, the balance between the need for speed of thought and for sheer physical presence shifts against these opponents.

That, then, takes us to the debate between the qualified vet and the qualified doctor for the No.3 shirt.

Ever since Euan Murray opted to withdraw his services on Sundays because of his religious beliefs, the tendency has been to presume that, as long as he has proven his physical fitness, he will come straight back into the team as soon as he is available.

The accompanying table in which he sits second, albeit admittedly quite distantly so, tends to reinforce the point that Scotland generally do better when he is in the team and that suggests he will once again be invited to pack once again with the comrades he presumably deems to have sinned last weekend.

Again, however, there are other considerations and in terms of morale you have to wonder what sort of message it will put out if, after the latest signs of Cross becoming more comfortable in the Test arena, the man in possession. who scored the one try Scotland earned through their attacking play against the All Blacks, is dropped. This is the additional predicament that Murray's situation gives the management, who have been given a difficult enough job in having to work out ways of taking on the world's top two sides in seven days.

My expectation today is that, whereas, for what it is worth, I would include Barclay, Cross and Kellock in the XV to line up against the Springboks, the only changes Robinson will make to last Sunday's side will be to bring in Denton and Murray.