The trouble is when you take the lead spinner out of the side, who bowls those 20 overs? It's all very well and good to champion the part timers when they do the part-time thing, but what about when they have to bowl, no matter what? It's a different story.
In South Africa, they found the loophole, using a steady medium-pacer, whose overs were both effective and brief enough to serve as a sacrifice to the match referee. It seems unlikely that McDonald is in calculations for Cardiff, however. Is that because they expect Stuart Clark to do the same thing or are they just being foolhardy?
It's certainly not the least of all concerns that the player who would be the no. 1 spinner in the absence of Hauritz, North, is not actually doing anything at no. 6 with the bat.
I tend to think that if McDonald is not really there to play at all and if Hauritz isn't there to be the core spin bowler, then there has been a selection error.