Balard is a good example. Rowles and Bos are other examples.
Nisbett is not. Similar to Balard he had a couple of great quality seasons at Central Coast. But hasn't been able to start every week in Scotland.
Irunkunda is not. Often a bench player for Adelaide, similar situation at Bayern reserves in the fourth division. He has huge potential, but there are big flaws in his game.
Guys like Brimmer, has a stand out season but has other periods where his form has not been great. Piscopo had always been highly touted as a junior, but I don't remember anyone wanting him selected when he was at Wellington or Newcastle. A good period with Victory, fantastic, but show it to us for the whole year.
It's not a hard rule, I don't mind players like Nisbett being selected, but I'm not bothered if these guys miss selection. If someone truly stands out, they will be an easy selection (Cicati playing every week in Serie for a couple of seasons is the recent example).
To bring it back to the Popa out thread, I don't think any of these selections or non selections are mistakes and should impact on him being in the job. They are all about the same average level so he picks who he thinks can do a job in his system.