Starting a club game the week before an international is unusual for any player not seeking to prove physical fitness but so, too, is the decision to change playmaker after successive wins, particularly when the side has waited 12 years to do so in championship matches.
Those two victories over Italy and Ireland have earned Scott Johnson, the caretaker head coach, and his assistants the right to unorthodoxy and, in any case, no-one is kidding themselves that they were anywhere close to flawless performances.
"It's a fine line we take here . . . but we wanted him [Weir] to keep playing and get confidence in what he's doing," Johnson said yesterday. "I thought he played well the other night and he provides us with something different, but it's a tough gig out there in that position. It's a different skill-set and we're not disappointed in Jacko [Ruaridh Jackson]. There are areas of the game Jacko needs to work on but we're acknowledging that we need to improve certain areas of our game."
Johnson more or less agreed when asked whether he thought the change in such a pivotal position might wrong-foot the Welsh management.
"There's been a lot of pressure on Greig [Laidlaw] and we're trying to alleviate some of that so it's good if it surprises them," he responded. "They probably wouldn't have predicted it and that's not a bad thing, but the fact is I'm not so worried about Wales, I'm worried about us and trying to get us right."
In terms of what is best for Scotland, a key difference between Weir and Jackson has always been the way their onfield persona, consideration of which seemed to be reflected in the latest pithy offering from a man who was a stand-off himself, albeit one who did not reach the Test arena.
"It's a funny position," Johnson mused. "It's one that requires you to think like a man of action and act like a man of thought. It's a difficult position to play."
For those reasons it takes time for players to reach their potential, too and it is worth noting that, still only 21, Weir is three years younger than Jonny Sexton – considered a certainty to be the British & Irish Lions stand-off this year – was when he made his first Ireland start four years ago.
Yet Weir has been a contender since making his Scotland A debut three years ago and has always carried the natural swagger of the best exponents of this crucial position.
There have, of course, been mistakes aplenty in the time he has spent in senior professional rugby. However, what has been striking throughout is his demeanour.
Weir appears unaffected by setbacks and instantly looks for chances to bounce back.Saturday will, of course, be the biggest examination of his temperament thus far as he starts a Test for the first time and while all modern players know the right noises to make ahead of big games his choice of words rang true.
"The most nervous you will be is before the game during the anthems and all that," he said. "It is a nervous period but there are so many more proud emotions that come into your head at that time. Once the ball is in play for the first time during the game, then everything else will go to the back of my mind apart from the gameplan and what we want. The team will be on the front of my mind. I'm sure that I will not get caught up in the occasion too much."
His principal task is to try to ensure that if the Scottish pack does as well in the set-piece as it did against Ireland, their success in doing so can be made to tell to greater effect because of where they are winning the ball.
The strange juxtaposition between the way they performed in what are normally seen as key battlegrounds and Ireland's overall domination of possession was partly down to the fact that they were winning the ball in areas where they could not afford to hang on to it. That, of course, is not all down to half-back decisions, but the satisfaction with the way the forwards have gone about their business is shown by the fact that the only change to the pack is the now ritual return of Euan Murray after he has missed a match played on the Sabbath.
Johnson said that was no comment on Geoff Cross's efforts 10 days ago which were widely viewed as excellent, but merely an acceptance that Murray is a "world-class tighthead".
Up against what the coach believes is the one team in the championship which boasts a specialist openside – and with Sam Warburton returning yesterday in place of Justin Tipuric they boast not one but two – Scotland might have made a tactical switch by reintroducing John Barclay, now fit and fast returning to top form.
Al Strokosch, who started against England, was also available and, while Johnson admitted to considering both, it is clear that considerable confidence has quickly been formed in Rob Harley as a foil for the redoubtable Kelly Brown and resurgent Johnnie Beattie.
That sanguinity was best expressed in the way that Johnson indicated that the only real discussion about which back-row forward to bring in, which resulted in Ryan Wilson being rewarded for his exemplary efforts as Scotland A and Glasgow Warriors captain in recent weeks, related to the bench.
"We're trying to predict things on the bench and what might happen. We felt we had enough coverage of the guys there if something failed to cover it and Ryan provided something different," he explained.