it is independend from coach level, but maybe dependent on your stamina level ;)
he coach trys always to play with your best players, in the third they are fresh so they play in that moment if you had long time without a "break" in the game he sometimes send the complete second lineup in and it needs some time he change back(till they are again stronger then your backups + and he had a oppurtunity to change).
Sometimes in the last minutes the coach takes a time out to give your stars a rest.