International camps can be awkward when club schedules delay arrivals. The update says not every senior player will join at the same time, so adding younger bodies gives Scotland enough numbers to run proper sessions at Lesser Hampden.
That matters for more than fitness work.
The report adds that McFarlane is expected to stay on the trip as a training goalkeeper, which underlines the logistical side of this move as much as the developmental one.
There is also a clear evaluation angle. These are not random names pulled in to make up the squad.
That gives Clarke a closer look at players already on the radar, but in the environment that matters most: senior international training.
This is how national-team depth is built. First comes exposure to the tempo, standards and demands of the senior camp. Then comes the judgment on who can handle the next step. Scotland appear to be using a logistical gap to accelerate that process.
The next thing to watch is whether any of the four carry this week’s opportunity into a more permanent role once the full squad assembles and the United States trip begins.